Clara Maass reported for duty as a U.S. Army contract nurse on May 1, 1898, following the outbreak of the Spanish–American War.
When the Spanish–American War erupted in 1898, Clara Maass volunteered her services and was accepted as a contract nurse with the United States Army, formally reporting for duty on May 1, 1898.
Contract nurses occupied an unusual position in this era: they were civilian women hired to serve alongside the military but without formal military rank or the protections afforded to enlisted personnel, reflecting the U.S. Army's lack of an established, permanent female nursing corps at the time (the Army Nurse Corps would not be created until 1901). Maass served in military hospitals and camps in Florida, Georgia, and eventually Cuba, caring for American soldiers who suffered overwhelmingly from disease — particularly typhoid fever, dysentery, and yellow fever — rather than combat wounds, a pattern typical of the war.
Her willingness to serve in disease-ridden camps, often under difficult and unsanitary conditions with limited resources, demonstrated the courage and dedication that would define her career. This wartime nursing experience directly exposed her to the devastating toll of yellow fever on American troops stationed in the Caribbean, planting the seed for her later, fateful involvement in Walter Reed's experimental research into the disease's transmission in Havana.
Her service during this period exemplifies the vital but often overlooked contributions of civilian contract nurses to American military medicine before the formal establishment of a professional Army nursing corps.