Abstract. The Zeeman splitting at moderate magnetic fields (up to 334 G) of 20 lines of Nd II, covering the part 569.89 nm to 617.05 nm of the visible spectral range were investigated. We used a Doppler-free collinear laser ion beam spectroscopy technique supported by a precise computer analysis. From the Zeeman effect studies we re-investigated the Landé gJ factors for 20 odd levels between 22 850 and 30 002 cm and 11 even levels lying between 6005 and 12 460 cm −1 . We compared our data with other available experimental and theoretical values. We achieved an accuracy better than that of other authors, making our data valuable for future theoretical parametric studies.