The hydrophobic and electrostatic characteristics of bacterial cell surfaces were compared with attachment proclivity and biomass accumulation over time between wildtype Pseudomonas aeruginosa serotype O6 (possesses A and B band LPS), and three LPS-deficient mutants, vi;. A28 (A(+)B(-)), R5 (A(+)B(-)), and Gt700 (A(-)B(-)). The hydrophobic character of each serotype was determined by hydrophobic interaction chromatography and salt-aggregation, and strains were ranked similarly by each method, viz. R5 greater than or equal to A28 > Gt700 > O6. The anionic characteristics of cell-surfaces were determined by electrostatic interaction chromatography and by zeta-potential measurements, and ranked R5 > A28 greater than or equal to Gt700 > O6. Adhesion and biofilm accumulation on stainless steel were significantly different between strains, following the order R5 > A28 much greater than O6 > Gt700. Biofilm rankings were similar on glass, a second hydrophilic substratum. The mutant strains with a strongly hydrophobic character (R5 and A28) demonstrated a significantly greater capacity to form biofilms. These adherent mutants also appeared to have a more anionic cell surface, which may have played a role in biofilm formation on the hydrophilic substrata