BackgroundThere is a dearth of information on medication safety and counseling experience regarding paternal exposure (PEx) to drugs and chemicals in the peri‐conception period. The Motherisk Program, first established in Toronto, ON, Canada in 1985, is a teratology information and clinical consultation service with a focus on drug safety during pregnancy. Here, we reviewed for the first time our counseling experience with PEx.MethodsThis is an observational retrospective cohort study using a prospectively collected database. Telephone counseling records from Jan 1, 2002 to Dec 31, 2006, inclusive, were screened manually for PEx.ResultsOf a total of 157,933 telephone requests for counseling over this 5‐year period, there were 249 (0.16%) requests for counseling on PEx. Most of these calls (177/249) were referred by health professionals. Counseling for exposure to drugs was requested in the majority of cases, with the remainder being exposure to chemicals, radiation, infection, or combinations of the above. The four drugs on which counseling was most frequently sought were methotrexate (33 requests), finasteride (24 requests), azathioprine (20 requests), and prednisone (18 requests). For many drugs, there was a paucity of information on PEx.ConclusionThere is an ongoing need for safety data on PEx. Future studies are needed to evaluate the safety of PEx to selected drugs in the peri‐conception period.HSC Research Institute (CYL,GK); equal contribution (CYL,CJ)