In the past, addressing formal letters was simple, since most couples were happy to be addressed as "Mr. and Mrs. Last Name." However, today addressing letters can be much more fraught. It's common for unmarried couples to live together, for married couples to have different last names or for a variety of other etiquette traps to come up while addressing letters. If the couple you are writing to are both doctors, whether medical doctors or holders of doctorate degrees, you'll want to know how to address them correctly.
Writing to Two Doctors With the Same Last Name
There are a few different options for properly addressing a letter to two doctors. If both people are doctors, and they share a last name, you can simple address the letter to, for example, "The Doctors Smith." If you'd like to write a bit less you can abbreviate with "The Drs. Smith." Or you can write out each title, addressing the letter to "Dr. John Smith and Dr. Jane Smith." In this case, either person's name can come first. Finally, you could address the letter to "Drs. John and Jane Smith."
Writing to Two Doctors With Different Last Names
If you are writing to two doctors with different last names, you should spell out each title and name when you address the letter. For example, writing to two doctors at a practice, you would address a letter to "Dr. John Smith and Dr. George Winston." It is generally advised that you avoid writing "Drs. Smith and Winston." Instead of lumping their titles together, it's best to list them both separately in this case. In opening the letter, you should write "Dear Dr. Smith and Dr. Winston."
Writing to One Doctor and a Partner
If you're addressing a letter to a couple and only one partner is a doctor, the person who is a doctor is listed first. This is true whether the doctor is the male or female, if you're addressing a heterosexual relationship. This is because, when addressing a letter, the person with the highest social rank generally is listed first. For example, if the wife is a doctor and her husband is not, a letter would be addressed to "Dr. Jane Smith and Mr. John Smith." This form can be used whether or not the couples shares a last name. It can also be used no matter which partner is the doctor.
Alternatively, if the couple shares a last name you can address the letter to "Dr. and Mr. Smith," or "Dr. and Mrs. Smith."