This study explores patient knowledge of cancer diagnosis among underserved immigrant/migrant minorities. Patients were recruited at a hospital-based cancer clinic in New York City. Demographic and self-reported diagnosis and treatment information were collected; charts were reviewed to ascertain cancer diagnosis. Four hundred thirty-four patients were included. Eighty-seven percent preferred to speak a language other than English in the health care setting. Sixteen percent had incorrect knowledge of their cancer diagnosis. Multivariate analysis indicated that both preference for a non-English language and diagnosis of a "below the belt" cancer were jointly predictive of incorrect knowledge (LR = 17.01; p = 0.0002). "Below the belt" cancers included bladder, colorectal, gynecological, penile, prostate, and testicular cancers. Among this cohort of immigrant/migrant cancer patients, a considerable proportion was unaware of their correct cancer diagnoses. This may have a significant impact on subsequent cancer education, treatment, and care. Limited-English-proficiency patients may be at particular risk.