In the present study we examined how husbands' and wives' intrusive thoughts of prostate cancer (i.e., thinking about it when not meaning to) and avoidance (i.e., efforts to not think about cancer) related to their own and each other's average negative affect over a subsequent 14-day period. We examined whether congruence or similarity in intrusion about illness, but not avoidance, would be associated with less negative affect as this response to cancer could potentially facilitate adjustment. Fifty-nine husbands and wives completed measures of intrusion and avoidance after the diagnosis of prostate cancer and reported on their daily negative affect for 14 days. Using the actor-partner interdependence model, both patients and their wives who had high levels of intrusive thoughts experienced less negative affect when the other member of the couple also experienced high levels of intrusive thoughts. Those who had higher levels of avoidance had spouses who had higher levels of negative affect regardless of their own levels of avoidance. Congruence in responses to cancer may be adaptive for intrusion but not avoidance because the use of intrusive thoughts by both husbands and wives can allow couples to process the diagnosis of cancer, facilitating psychological adjustment, whereas avoidance does not. The current investigation adds to our understanding of how people within a marital dyad affect each other as they adjust to a cancer diagnosis.