The personality trait of alexithymia was assessed in 95 patients (35 male, 60 female) with affective illnesses, receiving lithium prophylactically, by means of Schalling-Sifneos Personality Scale (SSPS). The mean SSPS score was similar to that of the healthy population: only 8 patients had a score below 50 points. No relationship was observed between alexithymia score and age, diagnostic category (bipolar I, bipolar II, unipolar) and the duration of lithium therapy. Lower SSPS scores (i.e. high alexithymia) were found in subgroups of male patients with essential hypertension and female patients with lithium-induced obesity. The results suggest that alexithymic traits have no relationship to the pathogenesis of affective illness but may play some role in somatic symptoms emerging in affective patients on lithium prophylaxis.