The U.S. Surgeon General advocates the accumulation of moderate-intensity activity throughout the day to improve health. To test the effectiveness of signs to encourage use of stairs instead of escalators. Community intervention. Shopping center. 17901 shoppers. Signs promoting the health and weight-control benefits of stair use were placed beside escalators with adjacent stairs. The sex, age, race, weight classification, and use of stairs were observed. Overall, stair use increased from 4.8% to 6.9% and 7.2% with the health and weight-control signs, respectively. Younger persons increase their stair use from 4.6% to 6.0% with the health sign and 6.1% with the weight-control sign. Older persons almost doubled their stair use from 5.1% to 8.1% with the health sign and increased use to 8.7% with the weight-control sign. Differential use of stairs was observed between ethnic groups. Among white persons, stair use increased from 5.1% to 7.5 and 7.8% with the health sign and weight-control signs. Among black persons, stair use decreased from 4.1% to 3.4% with the health sign and increased to 5.0% with the weight-control sign. At baseline, lean persons used the stairs more often than overweight persons (5.4% and 3.8%, respectively). The health sign increased stair use to 7.2% among normal-weight persons and 6.3% among overweight persons; the weight-control sign prompted stair use to increase to 6.9% among persons of normal weight and to 7.6% among overweight persons. Simple, inexpensive interventions can increase physical activity. Research is needed to identify effective motivators to promote activity among black persons.