OBJECTIVE To investigate the association between pregnancy planning and orofacial clefts in the United Kingdom. METHODS Case-control study. METHODS Scotland and the Manchester and Merseyside regions of England. METHODS One hundred and ninety-one children born with nonsyndromic orofacial cleft, 1997 to 2000, and 247 controls. METHODS Cleft lip with and without cleft palate, and cleft palate. RESULTS There was an inverse association between planning for pregnancy and orofacial cleft in the offspring (odds ratio [OR] = 0.51, 95% confidence interval [CI] = 0.33-0.79). An unplanned pregnancy together with smoking in the first trimester of pregnancy resulted in almost treble the risk of a child with an orofacial cleft when compared with those who planned their pregnancy and did not smoke (OR = 2.92, CI = 1.50-5.65). CONCLUSIONS Planned pregnancies were associated with a lower risk of orofacial clefts. Isolation of the elements of pregnancy planning implicated in these results is difficult. Current preconception advice needs to reach a wider audience; however, for maximum impact, efforts are needed to reduce the numbers of unplanned pregnancies.