After retirement, Saruhashi established and funded the Saruhashi Prize to recognize Japanese women researchers in the natural sciences.
Following her retirement from active research, Katsuko Saruhashi established the Saruhashi Prize in 1981 (with award activity continuing through the late 1980s and beyond), using her own personal funds to create an annual award recognizing Japanese women scientists who serve as role models and mentors for younger generations pursuing careers in the natural sciences.
The prize was a culmination of her lifelong advocacy for women in science, following decades of institution-building efforts including her founding of the Society of Japanese Women Scientists in 1958 and the Association for the Bright Future of Women Scientists in 1980. Saruhashi believed that recognition and visible role models were essential to encouraging more women to pursue and remain in scientific careers, especially in a country where structural barriers and cultural expectations often pushed women out of research professions.
Unlike many scientific prizes named after male scientists and typically funded by institutions or corporations, the Saruhashi Prize was personally funded and administered by Saruhashi herself, reflecting her direct, hands-on commitment to changing the landscape for women in Japanese science.
The prize has since become one of the most prestigious honors a woman scientist in Japan can receive, and it is frequently cited alongside major international awards as evidence of the recipient's excellence and leadership. It remains one of Saruhashi's most enduring legacies, continuing to recognize outstanding women scientists decades after her death in 2007.