Opinion leaders are members within a social group with significant social influence over others. A guideline on urinary catheter care was introduced in three groups (A, B, and C) of two randomly allocated wards. Two opinion leaders per ward were identified by nurses in groups A and B with the use of a sociometric method. For education, in-service lectures for 30% of nurses and opinion leaders' tutorials for all nurses were used in group A; opinion leaders' tutorials alone in B, and lectures alone in C. Before and after the education program, the guideline's frequency of practice was assessed by surveying 30% of randomly selected nurses and by direct observation. Results of the survey were comparable for groups A and B and both groups were significantly higher (p less than 0.05) than C, suggesting that informational transmission by opinion leaders was superior to that by the lecture. However, practices by direct observation in group A were significantly better (p less than 0.05) than those in B, indicating that staff compliance is best achieved by using both opinion leaders and lectures. The lecture probably endorsed the opinion leaders' leadership, enhancing their ability to influence the staff.