The concept of cell adhesiveness was analyzed by looking for correlations between the adhesive behavior and measurable biological properties of different cell populations. Ten established lines of melanoma cells were assayed for passive deformability (by micropipet aspiration), active spreading (by measuring the height/diameter ratio after incubation on different surfaces), density and mobility of concanavalin A binding sites (by quantitative analysis of fluorescence microscopic images), spontaneous and concanavalin A-mediated agglutination (by measuring the number of cell conjugates resisting calibrated shearing forces), and binding to glass capillary tubes (with a quantitative assay of binding strength). Forty-four different parameters were thus measured, and each set of determinations was repeated 2 or 3 t at different days on each cell line. Analysis of variance was performed to assess the capacity of each parameter to discriminate between different lines. Correlations between different parameters were studied in order to understand a possible influence of cell intrinsic properties on the behavior of individual cells. The following conclusions were suggested by experimental data 1. Cell spreading ability, resistance to slow deformation within a micropipette and ability to form shear-resistant bonds, are independent properties. It is therefore suggested that different mechanisms rule the cell deformations on time scales of several minutes, tens of seconds, and fractions of a second. 2. Cell spreading ability may effectively influence binding strength only when adhesive stimuli are low, since in this case, cell stiffness is likely to impair the formation of extensive contact areas. 3. Individual cells may display marked heterogeneity within a given population, that emphasizes the danger of using averaged parameters to predict rare events (such as metastasis formation). 4. The most useful parameters to discriminate between different cell lines were, spreading ability and shear-resistant lectin agglutination, and substrate adhesion. It is concluded that cell adhesion is influenced by several measurable cellular properties that may display independent variations. The importance of a given parameter depends on the conditions of bond formation and rupture.