The relationship between beef bull libido and conception rate following a 21-day breeding period was investigated over two seasons. Libido was defined as the number of services completed during a 10-minute exposure to a restrained oestrous female. In the first year bulls which achieved a mean libido score of three or more services were compared with bulls which achieved a mean of one service. In the second year a mean score of six or more services was compared with a mean of three services. Bulls were joined as single sires at a bull to female ratio of 1:35 in the first and 1:40 in the second year. Libido, as measured in this study, did not influence conception rate significantly.