Women who are diagnosed with breast cancer can experience an array of psychosocial difficulties; however, social support, particularly from a spouse, has been shown to serve a protective function. This study examined the ways in which a woman's mood and her spouse's marital satisfaction influence a male partner's decision to provide such support. Pre-test data (including a baseline measure and a 30 day daily diary) from a larger intervention study and Multilevel Modeling (MLM) were used. Results show that on days in which women reported higher levels of negative or positive mood, they received more support. Also, women who were overall more positive tended to receive more support than those who were less positive, but overall levels of negativity had no effect. Finally, men who were more satisfied in their marriages provided more support to their wives, but remained responsive to women's mood. Implications of these findings are discussed.