This study analyses how the economic crisis influenced labour market in Turkey. Our primary aim is to examine how the global economic crisis that broke out in 2007 influenced underemployment in Turkey especially between the years 2007 and 2011. After the crisis some structural changes occurred in the Turkish labour market, which showed improvement in some indicators since 2004. We have observed a relatively rapid change especially in indicators of unemployment and atypical employment. In this study we have described the situation of underemployment since the year 2000 before and after the crisis and then we have tried to figure out what determines underemployment, by using a logistic regression model. Logistic regression or the logit model is a non-linear regression model that is designed for two dependent variables. The model uses the micro data sets of the household labour force surveys for the years from 2006 to 2011, prepared by the Turkish Statistical Institute (TUIK). The study argues that such factors as being male, young, not being a head of the family, having higher education, being divorced, working at home or in a small workplace, working on a wage, working unrecorded, working in rural areas and working in the agricultural sector are elements that increase the probability of underemployment.