This paper analyzes job transitions for part-time workers in Spain. The first section of the paper reviews existing literature that applies to the Spanish case. First, we selected a sample from the 'continuous sample of work history 2005b' of Spain's Social Security, with individuals who had a part time job in 2001. Then we analyzed their different job paths for the period 2001-2005. The resulting analysis shows 5 categories: individuals that continued working part-time, those who underwent from P/T to F/T jobs, those who ended up in unemployment or inactivity and those individuals who undertook more than a specific number of jobs. Finally, we estimated the probabilities for individuals to fall in any of these categories, by using variables such as sex, age, professional rank and job sector.