Little empirical research examines the extent medical social workers try to change attitudes, norms, expectations, and protocols to create a hospital environment that encourages their participation in ethical deliberations. The researchers developed an ethical activism scale that measured the extent medical social workers engaged in such ethical activism, confirming its reliability from data obtained from a sample of 162 medical social workers in 37 hospitals in the Los Angeles basin. They tested seven hypotheses that probed the extent specific ethics-training, organizational, and demographic variables influence the extent social workers engage in ethical activism. Data strongly suggest the need to expand ethics training to include tactics of ethical activism, since many social workers do not engage in ethical activism. Data also suggest the need to target such training to social workers in hospitals that are relatively unreceptive to social workers' participation in ethical deliberations, since social workers are least likely to engage in ethical activism in such settings.