This paper presents the results of an exploratory case-control study of paternal occupation as a risk factor for birth defects in offspring. With the use of a population-based registry in British Columbia, 14,415 liveborn children with birth defects were identified for the period, 1952-1973. Two controls were matched to each case by using the birth files of British Columbia. Paternal occupation was obtained from the birth certificate. The analysis included 20 birth defect categories. Paternal occupations found to be associated with an increased odds ratio (OR) of birth defects include janitors [hydrocephalus (OR = 5.04), ventricular septal defects (OR = 2.45), other heart defects (OR = 2.35)], forestry and logging workers [congenital cataract (OR = 2.28), atrial septal defects (OR = 2.03), syndactyly (OR = 2.03)], painters [spina bifida (OR = 3.21), patent ductus arteriosus (OR = 2.34), cleft palate (OR = 3.36)], printers [atresia of the urethra (OR = 4.50), clubfoot (OR = 2.18)], and plywood mill workers [patent ductus arteriosus (OR = 2.52), pyloric stenosis (OR = 4.12), dislocated hip (OR = 2.71)]. This study has several limitations and the results must be viewed with caution. Nonetheless, the study provides new leads for further evaluation of the role of father's occupation in the etiology of birth defects.