This study was carried out to determine therapeutic efficiency of intramammary lincomycin-neomycin infusions applied in lactating cows with subclinical mastitis and clinical ones. The udders were selected after clinical examination of the mammary gland and milk samples and bacteriological examination of udder secrete. The treatment included intramammary administration of 330 mg lincocin and 100 mg neomycin every 24 hours after milking for 3 consecutive days. The efficacy of the therapy was assessed by bacteriological and clinical cure (in clinically mastitis) In 97 subclinically diseased udders the efficiency of treatment depended on the infectious agent to 81.4, 92.0, 73.3, 88.9, 66.7 and 100.0% Staphylococcus aureus, Staphylococcus epidermidis, Staphylococcus spp., Corynebacterium pyogenes and Streptococcus agalactiae being the respective pathogens. In 17 cows with clinically mastitis the efficiency of treatment reached 100.0, 100.0, 66.7, 100.0 and 100.0% by clinical cure and 66.7, 100.0, 66.7, 100.0 and 100.0% by bacteriological cure in the cases induced by Staphylococcus aureus, Staphylococcus epidermidis, Staphylococcus spp., Streptococcus agalactiae and Escherichia coli, respectively. The bacteriological cure rate was 82.4% for the clinical conditions and 85.6% for cases of subclinical. The clinical cure was 94.1% for clinical cases. The present results indicate that lincomycin-neomycin combination was very useful for treating in lactating dairy cows with mastitis.