The study analyzed psychometric properties of a Spanish version of the Hurlbert Index of Sexual Assertiveness in a Spanish sample of 400 men and 453 women who had had a partner for the last 6 mo. or longer at the time of the study. Exploratory and confirmatory factor analyses suggested a two-factor solution with the factors Initiation and No shyness/Refusal. Internal consistency values for total scores were .87 and .83 for the factors, respectively. Convergent validity tests were also satisfactory. It is therefore reasonable to conclude that the Spanish version of the scale has appropriate psychometric properties.