Background:Pediculosis capitis and scabies are common parasitic skin diseases,especially in resource-poorcommun-ities,but data on epidemiology and morbidity are scanty. Objectives:To assess the prevalence, seasonal variation and morbidity of pediculosis capitis and scabies in poor neighbourhoods in north-east Brazil. Methods The study comprised cross-sectional surveys of a representative population of an urban slum (n=1460) in Fortaleza, the capital of Ceara State (Brazil) and a fishing community 60 km south of the city (n=605). Study participants were examined for the presence of scabies and pediculosis capitis. In a longitudinal study in the slum,variation of prevalence in different seasons of the year was assessed. Results:Prevalence of pediculosis capitis was 43.4%in the slum and 28.1%in the fishing community. Children aged 10-14 years and females were most frequently affected. Scabies was present in 8.8%of the population in the slum and in 3.8%of the population in the fishing community. There was no consistent pattern of age distribution. Superinfection was common in patients with scabies, and cervical lymphadenopathy in patients with pediculosis capitis. Multivariate analysis showed that age ≤15 years, being of female sex and living in the urban slum were independent factors contributing to the simultaneous coinfestation with pediculosis capitis and scabies. The longitudinal data from the urban slum showed a characteristic seasonal variation of pediculosis capitis, but no fluctuation of scabies. Conclusions: Pediculosis capitis and scabies are hyperendemic in the study areas and are associated with considerable morbidity. There is an urgent need to develop control measures for these parasitic skin diseases in resource-poor communities. This is the first community-based study describing in detail the epidemiology and morbidity of scabies and head lice infestation in Brazil. Background: Pediculosis capitis and scabies are common parasitic skin diseases, especially in resource-poorcommun-ities, but data on epidemiology and morbidity are scanty. Objectives: To assess the prevalence, seasonal variation and morbidity of pediculosis capitis and scabies in poor neighborhoods in north -east Brazil. Methods The study comprised cross-sectional surveys of a representative population of an urban slum (n = 1460) in Fortaleza, the capital of Ceara State (Brazil) and a fishing community 60 km south of the city (n = 605 Study participants were examined for the presence of scabies and pediculosis capitis. In a longitudinal study in the slum, variation of prevalence in different seasons of the year was assessed. Results: Prevalence of pediculosis capitis was 43.4% in the slum and 28.1% in the fishing community. Children aged 10-14 years and females were most frequently affected. Scabies was present in 8.8% of the population in the slum and in 3.8% of the population in the fishing comm unity. There was no consistent pattern of age distribution. Superinfection was common in patients with scabies, and cervical lymphadenopathy in patients with pediculosis capitis. Multivariate analysis showed that age ≤15 years, being of female sex and living in the urban slum were independent factors contributing to the simultaneous coinfestation with pediculosis capitis and scabies. The longitudinal data from the urban slum showed a characteristic seasonal variation of pediculosis capitis, but no fluctuation of scabies. Conclusions: Pediculosis capitis and scabies are hyperendemic in the study areas and are associated with considerable There is an urgent need to develop control measures for these parasitic skin diseases in resource-poor communities. This is the first community-based study describes in detail the epidemiology and morbidity of scabies and head lice infestation in Brazil.