Research indicates significant differences between nurse cohorts in many work-related factors. This study compared nurse competence between three generational cohorts comprising the current nursing workforce. The Nurse Competence Scale was used to collect data for this cross-sectional study from 2052 nurses in a university hospital in Finland. Data were analysed statistically. Significant differences were found between nurse cohorts in their competence. The length of work experience had a significant impact on the development of competence. The oldest cohort, with the longest work experience, had the highest competence scores (70.1 on a visual analogue scale), and the youngest had the lowest (59.0). All cohorts were most competent in patient-related nursing tasks, in maintenance of professional competence and in ethical care. Nurses were weakest in the development of nursing practice and the use of evidence-based knowledge. Targeted interventions in teaching–coaching for different nurse generations are needed to ensure the maintenance of nurse competence and high-quality patient care.