The purpose of this study was to investigate the effect of slime production in coagulase-negative staphylococci (CNS) on resistance to antibiotics. Ninety CNS strains of CNS isolated from different clinical specimens were studied. The strains had been isolated from urine (25 - 27.8%), blood (39 - 43.3%), catheter (15 - 16.7%), skin (4 - 4.4%), abscess (1 - 1.1%), throat (4 - 4.4%), nose (1 - 1.1%) and body fluid (1 – 1.1%). For the determination of slime factor production by the strains three different methods were used: Congo red agar, macro-tube and microplate. Using Kirby-Bauer disk diffusion test according to NCCLS standards the strains were investigated for resistance to vancomycine, teikoplanin, oxacillin, penicillin, chloramfenicol, erythromycine, tetracycline, levofloxacin, norfloxacin, trimethoprim-sulfamethoxazole and nitrofurantoin. The rates of slime production by the three methods mentioned above were found to be 84.4%, 75.6% and 75.6%, respectively. There was no statistically significant difference in sensitivity and specifity in the results obtained by these three methods. The slime positive groups were found to have higher resistance to tested antibiotics than slime negative groups. There was no statistically significant difference between slime positive strains and slime negative strains (p>0.05) with respect to resistance to some antibiotics such as penicillin, erythromycine, tetracycline, norfloxacin, trimethoprim sulfamethoxazole and nitrofurantoin except that oxacillin, chloramfenicole and levofloksasine. As a result, in CNS slime factor production was found to be very effective in terms of resistance to antibiotics.