Summary: Four studies are presented investigating the convergent validity, discriminant validity, and relationship with age of the Social Desirability Scale-17 (SDS-17). As to convergent validity, SDS-17 scores showed correlations between .52 and .85 with other measures of social desirability (Eysenck Personality Questionnaire-Lie Scale, Sets of Four Scale, Marlowe-Crowne Scale). Moreover, scores were highly sensitive to social-desirability-provoking instructions (job-application instruction). Finally, with respect to the Balanced Inventory of Desirable Responding, SDS-17 scores showed a unique correlation with impression management, but not with self-deception. As to discriminant validity, SDS-17 scores showed nonsignificant correlations with neuroticism, extraversion, psychoticism, and openness to experience, whereas there was some overlap with agreeableness and conscientiousness. With respect to relationship with age, the SDS-17 was administered in a sample stratified for age, with age ranging from 18 to 89 years. In all but the oldest age group, the SDS-17 showed substantial correlations with the Marlowe-Crowne Scale. The influence of age (cohort) on mean scores, however, was significantly smaller for the SDS-17 than for the Marlowe-Crowne Scale. In sum, results indicate that the SDS-17 is a reliable and valid measure of social desirability, suitable for adults of 18 to 80 years of age.