This paper studies the determinants of self-employment in Québec and in the rest of Canada by focusing on liquidity constraints, age and aggregate unemployment. We use a random effects probit model to analyse panel data from the Survey of Labour and Income Dynamics (SLID) for the period 1993-2010. The main results are as follows. The positive effect of investment income on the probability of being self-employed confirms the existence of liquidity constraints. Being older increases the probability of choosing self-employment, rather than salaried work. This suggests that working for oneself may be a stepping stone towards retirement. High unemployment decreases the probability of being self-employed, suggesting that pull factors dominate push factors.