Many investigators have reported the increasing incidence of pervasive developmental disorders (PDD), noting that this is probably due to more precise diagnoses, as a result of professionals' increased awareness and knowledge, as well as increased publicawareness. Child mental health services are usually the first to examine these patients and consequently are required to deal with this increase on a practical basis. The aim of this study is to investigate the factors which may be responsible for this increase in PDD cases in a communitymental health centre over a ten year period and to examine whether this has led to a differentiation in service delivery. Consequently, two sets of factors are investigated: factors pertaining to the children themselves, as well as their families and factors related to service provision and delivery.48 children, aged between 2 and 6 years (Mean: 3,5 yrs) with pervasive developmental disorder, as well as their families are divided into two groups according to year of intake. Data collected from patient files included prenatal and perinatal information; medical the and developmental history;family functioning; and hereditary factors. Data from the Service included professionals involved in each case; number of diagnostic sessions; referral for further examinations; patient's symptoms and level of functioning; cognitive functioning; recommendations and outcome. There was no significantdifference in age at intake between groups. The number of cases with pervasive developmental disorder has doubled over a ten year period at our Service. There was no significant difference between groups, with regard to conception, perinatal, developmental and medical histories. Thereis a trend for increased non-medical referrals. Service delivery has not differentiated over the ten year period. In conclusion, no specific factors were identified to justify the increase in PDD cases at our Service over a ten year period, however the trend for more non-medical referrals seems toimply a rise in public awareness of these disorders. Despite augmented patient intake without the complementary increase in staff, service provision at our setting has remained stable, delivered according to a multidisciplinary model and designed according to individual patient needs.