Objective: To investigate the reproducibility of an adapted optical leg volume meter and to determine intraindividual volume changes of the lower legs on separate days and in the course of a working day in healthy volunteers. Design: Adaptation of a standard optical leg volume meter, ‘volometer’, and calibration on an artificial leg and on volunteers. Study of the behaviour of lower leg volume in volunteers. Setting: Free University Hospital, Amsterdam. Participants: Thirty-six healthy volunteers, workers in the hospital. Intervention: The lower leg volume was measured on five or six different days at the beginning and end of a full working day. Main outcome measures: Reproducibility of the adapted volometer, and volume changes of the lower legs at different times. Results: Adaptation of the volometer resulted in a reproducibility of 0.07% in an artificial leg and of 0.46% in volunteers. A significant increase ( p<0.0001) in the volume of the lower legs in the course of the day was observed. Conclusion: Adaptation of the optical leg volume meter resulted in reproducible recordings of the volume of lower legs. In the course of the day an increase in volume occurs.