Despite the extensive literature on work ability, few studies have looked at variables associated with work ability of nurses working fixed versus rotating shifts. The study aims were to explore variables contributing to work ability and to examine the association of demographic, job satisfaction, and work shift to work ability. A cross-sectional design was utilized to assess work ability level and job satisfaction among nurses working 8 or 12 hour rotating or fixed shifts in Jordanian hospitals. The data collection tools were the Work Ability Index and the Mueller/McCloskey Satisfaction Scale. Data were analyzed to determine the extent to which job satisfaction, shift work, and demographic variables were associated with work ability. Work ability level was "moderate", while job satisfaction level was "moderately dissatisfied". A positive significant relationship was found between work ability and job satisfaction (r = 0.347, n = 349, p < 0.000). This relationship was higher for fixed-shift workers (r =.507) compared to rotating-shift workers (r = .299). Standard linear multiple regression analysis indicated that job satisfaction level predicted work ability level (β =.347, p = .000). The study confirmed that promoting job satisfaction leads to higher work ability, and thus, enhances the quality of care provided. The finding that job satisfaction is predictive of work ability has implications for training intervention.