Trial registration helps minimize publication and reporting bias. In leading medical journals, 96% of published trials are registered. The aim of this study was to determine the proportion of randomized controlled trials published in key nursing journals that met criteria for timely registration.We reviewed all RCTs published in three (two general, one mental health) nursing journals between August 2011 and September 2016. We classified the included trials as: 1. Not registered, 2. Registered but not reported in manuscript, 3. Registered retrospectively, 4. Registered prospectively (before the recruitment of the first subject into the trial). 5. Timely registration (as 4 but the trial identification number is reported in abstract).We identified 135 trials published in the three included journals. The majority (n = 78, 58%) were not registered. Thirty-three (24%) were retrospectively registered. Of the 24 (18%) trials that were prospectively registered, 11 (8%) met the criteria for timely registration.There is an unacceptable difference in rates of trial registration between leading medical and nursing journals. Concerted effort is required by nurse researchers, reviewers and journal editors to ensure that all trials are registered in a timely way.