Sinonasal cancers often masquerade as chronic inflammatory conditions of the upper respiratory tract, and thus they may progress unrecognized and untreated. In Nigeria, early diagnosis is complicated by other factors, including poverty, illiteracy, and a lack of adequate medical services and equipment. In an effort to quantify some of the characteristics of sinonasal cancer among Nigerian Africans and to document some unusual findings that may or may not be unique to this population, we conducted a prospective 7-year study of 27 patients-18 males and 9 females, aged 7 months to 85 years (mean: 49.8 yr)--who presented to our department with features of sinonasal cancer. These 27 cases represented 8.1% of the total number of head and neck cancers (n = 335) seen at our institution during the study period. With respect to the probable site of origin, antronasal tumors were the most common (n = 21 [77.8%]), followed by tumors of the nasal cavity (n = 4 [14.8%]) and the antrum (n = 2 [7.4%]). Among the many presenting signs and symptoms, the most common were nasal obstruction (n = 24 [88.9%]), nasal discharge (n = 24), epistaxis (n = 22 [81.5%]), and buccal swelling (n = 21 [77.8%]). The duration of symptoms ranged from 6 weeks to 3 years (mean: 7.2 mo). Four particular findings were unusual in this study: (1) the sizeable proportion of adults (18.5%) who presented at a relatively early age, (2) the high percentage of tumors (77.8%) that were of antronasal origin, (3) a lack of ethmoid sinus involvement, and (4) the small percentage of patients (7.4%) who exhibited radiographic evidence of bony wall destruction despite advanced disease. However, the significance of these unusual findings is debatable in view of the small number of patients in our study.