The objective of this study was to analyse clinical and serological associations of anti-Ki antibodies. Thirty-five patients with anti-Ki antibodies, detected by CIE, selected from laboratory routine, were studied. All patients were affected by autoimmune diseases: SLE and pSS were the most frequent diagnoses. The cohort was constituted by 27 female and eight males. Main clinical features were skin involvement (60%), xerophtalmia (48.6%), Raynaud's phenomenon (43%), photosensitivity (34%), xerostomia (31.4%). CNS involvement was present in four (11.4%) and renal disease in seven cases (20%). ANA, anti-dsDNA and RF were detected in 100%, 60% and 34.5%. In SLE, anti-Ki was detected in 6% of cases, more frequently in males compared to other SLE patients without anti-Ki (P < 0.004). Nineteen anti-Ki positive patients affected by SLE showed more frequently malar rash and multiple autoantibody specificities compared to 16 anti-Ki positive patients with other diseases (P = 0.044 and P = 0.0003, respectively). Our study confirms a preferential occurrence of anti-Ki antibodies in patients with sicca and skin involvement. Malar rash and multiple ANA specificities were significantly associated with SLE compared to other diseases in our study. Anti-Ki were detected in 6% of patients with SLE with a significant prevalence in males.