The dependence of composition and morphology of Tl2O3/Co3O4 composites on the experimental variables chosen for their anodic deposition (i.e., concentration of Co3O4 particles in suspension, electrode potential, electrolysis charge, and angular speed of the electrode) has been investigated. The composite layers have been tested as electrode materials for oxygen evolution from basic media, and found to be rather effective electrocatalysts characterized by the following features : overpotential (eta) at j = 100 mA cm(-2) ca. 475 mV, Tafel slope close to 60 mV decade(-1), linear dependence of j on [OH-]. Significant electrocatalytic activity could be achieved with a Co3O4 loading as low as 2.10(-5) g cm(-2). The electrode performance was maintained during a 14 day electrolysis carried out at room temperature with j = 100 mA cm(-2). Partial reduction of the composite layer was found to activate the composite electrodes, by decreasing eta to ca. 415 mV (at j = 100 mA cm(-2)). However this activation was not long lasting.