Fifty‐three strains of Micrococcaceae isolated from Spanish sheep's milk cheeses were subjected to numerical analysis using 43 unit characters. At the 80% similarity level (SSM) nine clusters (49 strains) were observed. At the 53% similarity level (SJ) nine clusters were also found. Cluster composition was not markedly affected by the coefficient used. Novobiocin‐resistant, coagulase‐negative staphylococci formed clusters of closely related species. However, novobiocin‐sensitive, coagulase‐negative strains fell into heterogeneous groups. The test that best separated the nine groups formed with both coefficients (SSMandSJ) was urease production. Aesculin hydrolysis, haemolytic activity (SSM), oxidation of mannose and phosphatase production were also useful c