Authors have collected the month of birth of: a) 500 children diagnosed and treated for allergy; b) 500 children treated for other pathological conditions and in which any indicative sign of atopy have been discarded, and c) Total of births in the different months of the years 1977-78 and 1979 in our hospital. Authors carried out statistic evaluation of numbers found and among affected from pathological allergy, April births present a standard deviation of more than 2,09; a deviation not present in other studied groups. Findings show that in our medium, to be born in April, signifies an important allergic risk, in relation with being born in any other month.