Thunderbird's Address Book can import CSV files. So save your Excel spreadsheet as a CSV file and try importing that. In the Address Book, Tools|Import|Address Books|Text File and browse to your CSV file. It works most smoothly if you rearrange the columns in the spreadsheet/CSV file to match the ordering in the list given here: http://kb.mozillazine.org/Import_address_list_from_text_file First Name, Last Name, Display Name, Nickname, Primary Email, Secondary Email, Work Phone, Home Phone, Fax Number, Pager Number, Mobile Number, Home Address, Home Address2, Home City, Home State, Home Zipcode, Home Country, Work Address, Work Address2, Work City, Work State, Work Zip, Work Country, Job Title, Department, Organization, Web Page 1, Web Page 2, Birth Year, Birth Month, Birth Day, Custom 1, Custom 2, Custom 3, Custom 4, Notes I have an article about importing a CSV file here: http://xenos-email-notes.simplesite.com/417788922 Look at the section titled "From somewhere else to Thunderbird". Now, I have a vague recollection that you need to save the fie in a particular encoding. Here's what I think we need to do… Excel doesn't offer the required encoding, so after doing the re-organizing, save the CSV file and then open it in a text editor which can re-save it in UTF-8 encoding.