Marketing Letter for Agencies: Why Direct Mail Goes First

A marketing letter is a short, personal letter posted to a business owner before you email or call. For an agency it works as an opener because few competitors send one, a letter reaches the owner's desk, and it gives every later email a reason to exist. One page is enough.

This guide to direct mail for agencies explains why the letter goes first, what to put in it and how to build the steps that follow.

Why would an agency send a letter in 2026?

Because the inbox is full and the mailbox is not.

A local business owner gets cold emails from agencies every week. Most say the same thing and most are deleted unread. A sealed letter addressed by name to the owner is rare. It gets opened, usually by the person you wanted to reach.

Marketers who measure it rate the format well. In the ANA's Response Rate Report 2021, which surveyed 581 qualified marketers, letter-sized envelopes produced the best return of any mail format sent to prospect lists, at 112% (ANA). The same report found that only 38% of respondents used direct mail at all, against 82% for email.

That report is a few years old and covers all industries, so treat it as direction. The pattern is still worth noticing. The channel fewer people use is the one that performs for prospects.

A newer figure covers response. Prospect lists average a 4% to 5% response, depending on format and targeting, according to PI World, citing the 2024 ANA Response Rate Report. That is an average. It is no forecast for your own letter.

There is a second reason, and it is about trust. A letter costs money and effort to send. The owner knows that. It signals that you chose them, which an email sent to 2,000 addresses cannot do.

Letter, postcard or parcel?

For first contact with a business owner, a direct mail letter wins. It looks like correspondence. A postcard looks like a flyer.

What goes in a marketing letter?

One page. Five parts.

1. Their name and business, correctly spelled. "Dear Dr. Patel", never "Dear Business Owner".
2. What you saw. One specific finding about their business. This is the whole reason for the letter.
3. What it costs them. One sentence, in their terms. Missed calls, lost bookings.
4. Who you are. Two sentences. What you do and one piece of proof.
5. One easy next step. A phone number, a short link, and a note that you will follow up by email.

Sign it by hand if you can.

An example

The business and the details below are made up.

Dear Dr. Patel,

I opened Brightside Dental's website on my phone last week. It took just over six seconds to load, and the "Book an appointment" button sits below three screens of text.

Most people looking for a dentist search on their phone. Many of them will leave before they ever see that button.

I run a small web design studio here in Mesa. We rebuild websites for local practices, and I've put together three changes I would make to yours first.

Could I show you? It takes ten minutes. You can reach me on 555-0142 or at the address below. I'll also send you a short email on Thursday with the details.

Kind regards,
[Signature]

That is 115 words. It names one problem, explains the cost and asks for ten minutes.

What makes a letter fail?

• It is about you. Three paragraphs on your agency's awards before a word about the reader.
• It could be for anyone. "We help businesses like yours grow online."
• It asks for too much. A 60-minute strategy session is a big ask from a stranger.
• It looks like junk. A window envelope with a printed indicia and "Important information inside".
• It stands alone. A single letter with no follow-up wastes the attention it earned.

What happens after the letter?

The letter opens the door. Email and LinkedIn keep it open.

Leadodo's Outbound Machine runs six steps over 19 working days, and the order is worth copying even if you send by hand.

When a business replies, every later step stops for that business. Nobody who has answered should receive another automated message.

The emails are easier to write once a letter has gone out. Your subject line can be "The letter I sent to Main Street", which no other agency in their inbox can use. Our follow-up templates include one built for exactly this, and our subject line guide has more.

Who should get a letter?

A letter costs more than an email, so the list matters more.

Send to businesses where three things are true. One new customer is worth a lot to them. You can name a specific problem with their current website. And you can find the owner's name.

Sending a letter to every business in a zip code is how print vendors sell postcards. It is not how an agency wins clients. Our test of 3,570 cold emails showed how much the list matters. Businesses with the weakest 20% of websites replied positively about 3.2 times as often as the rest, to the same message. The full numbers are in our write-up.

That test was run on email. We have not yet published the same comparison for letters, so we make no claim of our own here about letter reply rates.

For ways to build the list, see how to find businesses without websites and the nine signs a business needs a new site.

How do you send letters without it taking all week?

You have three routes.

1. By hand. Print, sign, fold, stamp. Fine for 20 letters. Each one takes a few minutes once the text is written.
2. A print-and-mail service. You upload a list and a template, and the service prints and posts. You still write each personal finding yourself.
3. A tool that does both. Leadodo finds the businesses, Twip scores each website and writes the first line from what it found, and your Outbound Machine posts the letter and sends the emails and LinkedIn steps after it. In the US, a posted letter costs about 86 cents, for one page in black and white, sent First Class. That covers printing, postage and the envelope.

Whichever you choose, read what goes out before it goes. You are putting your name on paper on someone's desk.

What should you check before posting?

• The owner's name and the address, against the business's own website or Google listing
• That the finding is still true today
• That your return address is on the envelope
• That your email follow-up is scheduled for 3 days after the letter should arrive
• The postal rules for your mail class. The US Postal Service publishes them, and bulk rates have their own requirements.

Where can you go deeper on direct mail?

Each part of this guide has its own page.

• Direct mail marketing, the broad guide to the channel
• What direct mail costs per piece
• Direct mail examples for B2B
• Sample sales letters to copy, and how to write a sales letter
• Business introduction letters
• Postcard or letter, and when lumpy mail is worth it
• Automated direct mail and how to plan a direct mail campaign

Questions

Does direct mail still work for B2B?

It can, when the list is small and the letter is specific. The ANA's 2021 survey of marketers found letter-sized envelopes gave the best return of any mail format for prospect lists. Few agencies send letters, which is a large part of why one stands out.

How long should a marketing letter be?

One page, and 100 to 200 words is plenty. The letter has one job, which is to earn a reply or a recognized name when your email arrives.

Is a letter better than a cold email?

They do different jobs. A letter is far more likely to be noticed and far more costly to send. An email is cheap and easy to reply to. Sent together, with the letter first, each makes the other stronger.

Should the letter be handwritten?

A typed letter with a handwritten signature is enough for most agencies. A fully handwritten letter suits a short list of high-value prospects. A printed "handwriting" font fools nobody.

How soon after the letter should I email?

About 3 days after the letter should have arrived. Soon enough that the owner remembers it, and late enough that the two do not land together.

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Next step. See how your Outbound Machine posts the letter and runs the 19 days after it. Outbound Machine.