Utilization of personal and professional support networks by parents varies over the life cycle of their mentally retarded children. Data from a mail survey questionnaire, completed by 330 parents, were analyzed according to four stages in the life cycle: preschool (birth to 5 years old), elementary (6 to 12 years old), teenage (13 to 18 years old), and young adult (19 to 21 years old). In general, parents of younger children utilized more services and support networks and were more supportive of mainstreaming; parents of older children were less supported, more isolated, and more in need of expanded services.