Originally conceived as a psychosomatic phenomenon, the alexithymia construct is today viewed as a personality dimension of subjects with unspecific vulnerability to disorders of affect regulation. In the past some Rorschach indices have been developed to measure the construct of alexithymia, leading however to controversial results mainly because of methodological problems. This paper reports the updated results on the construct validity of alexithymia variables from the Rorschach Comprehensive System (CS). In the first analysis, alexithymic patients scored in the expected direction in 6 clusters of fantasy, affect, adaptive resources, cognition, social adaptation, and projection. Also a hierarchical regression analysis showed that variables in the clusters of fantasy (movements), affect (WSumC), cognition (Lambda), and interpersonal relationships (Pop, CDI, PureH, SumT) predicted alexithymia. Finally a CS constellation index for alexithymia including 6 variables is shown. Analysis of sensitivity and specificity showed that this index correctly classified 90% of alexithymic patients.