INTRODUCTION: Inpatient rehabilitation is extremely important for patients recovering from cardiac surgery. Although a walking diary is routinely used in clinical practice, it has yet to be adequately tested and reported in the literature. OBJECTIVES: To establish whether the use of a walking diary affects the number of steps taken following cardiac surgery and whether this is related to the patient’s level of cardiac anxiety. METHODS: An open, controlled, randomized clinical trial was conducted with adult patients submitted to elective valve and/or coronary surgery, who had no motor impairment. All the participants used a pedometer to register the number of steps taken over five consecutive days in the hospital. Twenty-nine individuals were randomized to create an intervention group that used the walking diary as a treatment strategy, while twenty-three were allocated to a control group. The Mann-Whitney test was used to compare the number of steps between the two groups, while Spearman’s correlation coefficient was performed to evaluate the relationship between the number of steps and the level of cardiac anxiety. Statistical significance was defined as p<0.05. RESULTS: The groups were similar regarding their demographic, clinical and surgical characteristics. There was no difference between the groups regarding the total number of steps taken: control group=1,496 (477.5 - 2992.5) vs. intervention group=1,468.5 (494.2 - 2,678) (p=0.902). CONCLUSION: The use of the walking diary had no effect on the number of steps taken and was unassociated with the level of cardiac anxiety in inpatients following cardiac surgery.