Thanks for your response, Liz. Yes, I had declared the procedure "Public" -- and that's why I'm so puzzled. When I still got the same "...not defined..." error msg, I realized I needed professional help(!). Procedure was originally an event procedure triggered by a control on the main form (Form A). All the the actions/statements in that procedure relate to controls on Form A, and it is not really accessed by multiple forms, so is convenient to leave it as part of Form A rather than create a separate module. I know there are other ways to get the job done rather than open a pop-up (Form B), but pop-up forces the user to make a decision (thereby setting a variable which determines how the procedure acts) -- and the darned thing oughta work anyway! So I'm determined to prove I'm smarter than a few lines of code(!). So far the code is winning. Is there something I might be missing in the declarations section that would help Form B find the procedure in Form A? I've been operating on the assumption that "Public Sub..." is all that's necessary...