Contemporary immigration scholarship has typically treated immigrants with diverse racial backgrounds as a monolithic population. Knowledge gaps remain in understanding how racial and nativity inequities in mental health care intersect and unfold in midlife and old age. This study aims to examine the joint impact of race, migration, and old age in shaping mental health treatment. Pooled data were obtained from the Canadian Community Health Survey (2015-2018) and restricted to respondents (aged ≥45 years) with mood or anxiety disorders (n = 9,099). Multivariable logistic regression was performed to estimate associations between race-migration nexus and past-year mental health consultations (MHC). Classification and regression tree (CART) analysis was applied to identify intersecting determinants of MHC. Compared to Canadian-born Whites, racialized immigrants had greater mental health needs: poor/fair self-rated mental health (odds ratio [OR] = 2.23, 99% confidence interval [CI]: 1.67-2.99), perceived life stressful (OR = 1.49, 99% CI: 1.14-1.95), psychiatric comorbidity (OR = 1.42, 99% CI: 1.06-1.89), and unmet needs for care (OR = 2.02, 99% CI: 1.36-3.02); in sharp contrast, they were less likely to access mental health services across most indicators: overall past-year MHC (OR = 0.54, 99% CI: 0.41-0.71) and consultations with family doctors (OR = 0.67, 99% CI: 0.50-0.89), psychologists (OR = 0.54, 99% CI: 0.33-0.87), and social workers (OR = 0.37, 99% CI: 0.21-0.65), with the exception of psychiatrist visits (p = .324). The CART algorithm identifies three groups at risk of MHC service underuse: racialized immigrants aged ≥55 years, immigrants without high school diplomas, and linguistic minorities who were home renters. To safeguard health care equity for medically underserved communities in Canada, multisectoral efforts need to guarantee culturally responsive mental health care, multilingual services, and affordable housing for racialized immigrant older adults with mental disorders.