There are no available studies assessing job satisfaction amongst nursing staff in Spanish prisons. The aim of this study is to establish overall levels of job satisfaction and determine each of the components. Cross-sectional and multi-centre descriptive study conducted in Spanish prisons. A Font Roja satisfaction questionnaire adapted by J. Arranz for the study was used to measure degrees of job satisfaction using a Likert's scale. A parametric test was used and a regression model was constructed for predictive ends. 376 nurses answered the questionnaire (Participation Rate 62.7%; Response Rate 76.7%) 67 centres took part (91.8%). The average satisfaction mark was 2.84 (CL 95%: 2.81-2.87). The lowest ranked components were job variety 1.66 (CL 95%: 1.58-1.74), job-related stress 2.15 (CL 95%: 2.08-2.23) and control over job 2.77 (CL 95%: 2.73-2.82). The highest ranked aspect was job satisfaction, averaging 3.52 (CL 95%: 3.44-3.58). The average satisfaction mark for prison nursing staff was low when compared to other groups of health care professionals, which implies the need for corrective measures.