Aim The aim of this study was to determine which organisational socialisation contents affect turnover intention in newcomer nurses within their first 2 years of employment. Background Strategies to decrease turnover are a priority for improving organisational stability, reducing costs and enhancing effective nursing care. Materials and methods A cross-sectional design was employed, and standardised scales were used. The sample was divided into three groups: 0–6, 7–12 and 13–24 months of employment. Regression analyses were performed. Results A total of 156 Italian nurses participated in this study. In the 0–6 months group (model 1), the main factors that decreased turnover intention were competence acquisition (β = −0.42, P < 0.01) and comprehension of organisational rules (β = −0.38, P < 0.01). In the 7–12 months group (model 2), workgroup integration was relevant (β = −0.33, P = 0.02) and in the second year (model 3), the main factor was opportunities for professional development (β = −0.30, P = 0.05). Conclusions Newcomer nurses were sensitive to different organisational socialisation contents over time. This result supports planning different on-boarding strategies to enhance organisational socialisation success and to improve nurse retention. Implications for nursing management Useful strategies to improve retention include enhancing task mastery and workgroup integration at the ward level and a professional development plan at the organisational level.