ABSTRACT:Micro (and possibly panel) data from the Labour Force Surveys are a valuable source for analysing the labour supply behaviour. Among the information collected by the quarterly Italian Labour Force Survey conducted by ISTAT (the Italian national statistical agency), there are data on the duration of job‐search.From a single survey, one can only know the duration of search up to the time of the interview. Nonetheless, by appropriately exploiting the longitudinal structure of the survey (the sample scheme is a rotated one, with a 50|X% overlapping of the sample units in two subsequent quarters) it is possible to measure, although imperfectly, some completed spells of job‐search.In this paper, we try to model the duration of job‐search for a sample of young unemployed. Considerable attention is devoted to the measure of duration of search, and to the evaluation of its accuracy. A one state proportional hazard model is specified and estimated, accounting also for unobserved heterogeneity.The model is estimated on a sample of young (15 to 29 years old) unemployed in January 1986 reinterviewed in April, in an Italian region (Lombardy).The major finding is a fairly clear evidence, both for males and females, of negative duration dependence, even after accounting for the unobserved heterogeneity that turns out to affect the female popul