Objective: To analyze the impact of intra-urban atmospheric conditions oncirculatory and respiratory diseases in elder adults. Methods: Cross-sectional study based on data from 33, 212 hospitaladmissions in adults over 60 years in the city of S‹o Paulo, southeastern Brazil, from 2003 to 2007. The association between atmospheric variablesfrom Congonhas airport and bioclimatic index, Physiological Equivalent Temperature, was analyzed according to the district's socioenvironmentalprofile. Descriptive statistical analysis and regression models were used. Results: There was an increase in hospital admissions due to circulatorydiseases as average and lowest temperatures decreased. The likelihood ofbeing admitted to the hospital increased by 12% with 1¡C decrease in thebioclimatic index and with 1¡C increase in the highest temperatures in thegroup with lower socioenvironmental conditions. The risk of admission dueto respiratory diseases increased with inadequate air quality in districts withhigher socioenvironmentalconditions. Conclusions: The associations between morbidity and climate variablesand t comfort index varied in different groups and diseases. Lower andhigher temperatures increasedtherisk of hospital admission in the elderly. Districts with lower socioenvironmental conditiosshowed greater adversehealth impacts.