Using data from the Colombian Profamilia program for May 1969-December 1970 advantages of immediate postpartum IUD insertion are presented. Total IUD acceptors numbered 14922 42.6% of all deliveries during this time. More than twice as many women chose immediate as compared to delayed IUD insertion (11512 and 4826 women respectively). 94.8% of those choosing immediate insertion actually became acceptors compared to 45.4% of those choosing delayed insertion. When immediate IUD insertion was suspended temporarily only 43.4% of the women expressing a desire to return for insertion did so within 3 months of the appointment date. Of 2000 immediate postpartum insertions 44.8% were expelled within 30 days but in 94.6% reinsertions were carried out due to high motivation of the users and psychological preparation for expulsion. 58.9% of all insertions were active after 1 year. Pills offered immediately postpartum had a 95% dropout rate after 3 months. Good contraceptive education is essential for a larger number of IUD acceptors and higher continuation rates.