The study aimed to verify the opinion of family members about distress on cancer patients and the factors associated with it. Interviews with 140 family members of cancer patients were conducted. The Distress Thermometer was adapted to be used with family members. Approximately 72.9% of patients were considered in distress, related to concern (80.4%), nervousness (78.4%), sadness (74.5%), pain (67.6%), fatigue (67.6%) and problems with eating (57.8%). The hierarchical logistic regression models showed that while male (OR=0.025) and older ages (OR=0.006 to 0.059) had lower risk of perceiving the distress, individuals Protestants, compared to Catholics, were 12.77 times more likely to perceive it. About the associated factors, nervousness (OR=10.8) contributed significantly more to the perception of distress for family members when compared to fatigue (OR=3.38) or have private health insurance (OR=2.55). Family can be great allies in the evaluation and monitoring of distress in patients with cancer.