Frontal cells appear in two locations-in the frontal recess and in the frontal sinus. The aim of this study was to analyze the anatomic and clinical differences between the frontal cells at each location. The author reviewed 487 left and right sides of coronal computed tomography (CT) scans of the sinuses obtained from 300 consecutively presenting patients (600 sides) who were being evaluated for chronic sinusitis. For the purposes of this study, the frontal cells were classified according to location; group A cells were located in the area of the frontal recess (Bent and Kuhn cell types I and II), and group B cells were those that had invaded the frontal sinus itself (Bent and Kuhn cell types III and IV). The presence or absence of frontal sinusitis and concha bullosa was determined, as was the degree of frontal sinus pneumatization. Analysis revealed statistically significant differences between group A and group B in all three parameters; the prevalence of frontal sinusitis and hyperpneumatization of the frontal sinus was higher in group B, and the prevalence of concha bullosa was higher in group A (all p < 0.05). These findings imply that it might be more reasonable both clinically and anatomically to categorize frontal cells based on their location rather than on their Bent and Kuhn type.