Background Neuromuscular monitoring should be applied routinely to avoid residual neuromuscular block. However, anaesthetists often refrain from applying it, even when the equipment is available. We aimed to increase neuromuscular monitoring in six Danish anaesthesia departments via e-learning. Methods Interrupted time series study, with baseline data from a previous study and prospective data collection after implementation of the module, which was available for 2 weeks from 21 November 2016. We included all patients receiving general anaesthesia with muscle relaxants until 30 April 2017. Main outcome was application of acceleromyography, grouped as succinylcholine only and non-depolarising relaxants. Secondary outcomes were last recorded train-of-four ratio (non-depolarising) relaxants and score on a ten-question pre- and post-course multiple-choice test. Results The post-intervention data consisted of 6525 cases (3099 (48%) succinylcholine only, 3426 (52%) non-depolarising relaxants). Analysing all departments, we found a positive pre-intervention trend in application of acceleromyography for both groups, of estimated 7.5% and 4.8% per year, respectively (p < .001). The monitoring rate increased significantly for succinylcholine in two departments post-intervention (p = .045 and .010), and for non-depolarising relaxants in one department (p = .041), but followed by a negative trend of -37.0% per year (p = .041). The rate was already close to 90% at the time of the intervention and the mean last recorded train-of-four ratio was 0.97 (SD 0.21), also without a significant change. The median score on the post-course test increased from 7 (IQR 5-8) to 9 (IQR 8-10) (p < .001, Wilcoxon Signed-Ranks Test). Conclusion We found no overall effect of the e-learning module on application of neuromuscular monitoring, although the post-course test indicated an effect on anaesthetists' knowledge in this field. Trial registration Trial registration: Clinicaltrials.gov identifier: NCT02925143.