Although pts with CML receiving IM therapy are required to practice contraception while on therapy, there are isolated case reports of conception and pregnancy while on therapy. Here we present our experience with 18 pts who conceived while on IM therapy: 10 females and 8 males. All 10 females received IM for chronic phase (CP) CML. At the time of conception 1 had a complete cytogenetic (CG) response (CG CR), 3 a partial CG response (CG PR), 2 a minor CG response (CG MR), 2 complete hematologic response (CHR), and 2 no response. All pts stopped therapy immediately when pregnancy was recognized. Pts were managed with hydroxyurea (n=3), leukapheresis (n=1), interferon (n=1) or observation. Two pts had a spontaneous and 1 an elective abortion; 7 pregnancies continued uneventfully until delivery (median duration of pregnancy 36 weeks). Eight babies have been born (1 pair of twins): one had hypospadias, 7 were normal. The median age of the children is now 14 months (mo) and all are developing normally. At the time of delivery/abortion, 5 pts were 100% Ph-positive, 3 had still a CG MR and 1 a CG PR [i.e. 5 of 7 evaluable had increased Ph off therapy (1 not tested yet, 2 results pending) (median off therapy 9 months, range 4 to 22 months).] Pts re-started therapy after delivery and again after a median of 18 months after delivery (range 5 to 48 months), 3 have a CG CR, 2 CG PR, 1 CG MR, 2 CHR and 1 unknown. Among 8 males (6 CP, 2 AP) who impregnated their partners while on IM, 9 pregnancies resulted in the birth of 8 healthy babies and 1 spontaneous abortion. One baby had a mild rotation of the small intestine that resolved surgically. There were no complications of the other 7 babies. With a median age of 37 mo (range, 5 to 50), there are no known growth or development problems for any of the babies. This small experience suggests that conception while receiving IM is most frequently associated with a normal pregnancy and healthy babies, provided IM is immediately discontinued. Still, the recommendation to practice effective contraception while on IM should be enforced.