Rats were given long-term avoidance conditioning with a wheel-turn response, and with 0-, ½-, 2-, or 6-sec inescapable shock as punishment if no avoidance was made. All punishment groups showed severe decline in avoidance responding in the later sessions, though only for the ½-sec group was this clearly a decrement in discriminated avoidance. The 0-sec group showed a mild decrement and remained superior to all the punishment groups even when transferred to 2-sec punishment. Transfer sessions at the 0-sec condition showed punishment to have fairly permanent effects. "Nonescape" behavior increased with amount of inescapable shock. (PsycINFO Database Record (c) 2006 APA, all rights reserved)