Clinical isolates of coagulase-negative staphylococci were analyzed for elaboration of the capsular polysaccharide/adhesion (PS/A) and extracellular biofilm or slime. Of the 151 analyzed, 103 (68%) produced PS/A and 69 (46%) made extracellular slime; 87% of the slime-producing isolates made PS/A. Among isolates from all clinical infections examined except peritonitis, PS/A-positive isolates bound significantly (P < .001) more colony-forming units after 15 min to 1.5-cm segments of silicone-elastomer catheter than did PS/A-negative isolates. Slime-positive isolates were not more adherent than slime-negative isolates, because 42% of the PS/A-positive isolates were slime-negative. Thus, PS/A expression is common among clinical isolates of coagulase-negative staphylococci, accounting for most slime-positive and a proportion of slime-negative isolates.