Compliance with hand hygiene guidelines by hospital physicians and nurses is universally low and there is a need to apply powerful intervention methods from social sciences in order to improve compliance. One method is the formation of implementation intentions (or action planning) in which concrete ‘if then’ plans are formulated to link an environmental cue with performance of an intended behavioural action. This pilot study explored the practicality and effects of action planning on the hand hygiene behaviour (HHB) of nurses in an ICU and surgical ward of a university teaching hospital. A pre–post test design was used, and 17 nurses were invited to participate. A trained researcher observed HHB of nurses before and three weeks after the intervention in which action plans were formulated. Frequencies were calculated and logistic regression analysis was performed to assess changes in HHB. Of the 17 participants, 10 (seven in surgical ward, three in ICU) had complete data and were included in the analyses. In total, 283 potential moments for hand hygiene were identified, 142 in the surgical ward and 141 in the ICU. HHB increased from 9.3% at baseline to 25.4% post intervention (odds ratio: 3.3; confidence interval: 1.7–6.5; P<0.001). Although this was a small scale study, the results show promise for the use of action planning to improve the HHB of nurses in the short term. Action planning has shown success in closing the intention–behaviour gap in other fields, and its use for improving HHB in healthcare should be further investigated.