The authors investigated the hypothesis that partial fecal incontinence (PFI) had variable manifestations that can be categorized as different types of PFI with different pathogeneses and treatment. Anal and rectal pressures as well as external and internal anal sphincter electromyographic activity were recorded in 163 patients with PFI and in 25 healthy volunteers. Patients were treated with biofeedback or surgically. Three types of PFI were encountered: stress fecal incontinence (SFI; 55 patients), urge fecal incontinence (UFI; 72 patients), and mixed fecal incontinence (MFI; 36 patients). Anal pressure decreased in three groups in which MFI had the lowest pressure. A significant reduction in external anal sphincter electromyographic activity occurred in SFI, in internal anal sphincter electromyographic activity in UFI, and of both sphincters in MFI. Biofeedback cured 36 of 55 patients and postanal repair cured 10 of 19 patients with SFI. Forty-eight of 72 patients with UFI responded to biofeedback and 16 of 24 responded to internal anal sphincter repair. Biofeedback failed in MFI patients. Twenty-four of 27 patients who consented to operative correction of the sphincteric defect were cured. Three types of PFI could be identified: SFI, UFI, and MFI. Each type has its own etiology and symptoms, and requires individual treatment. Biofeedback succeeded in treating the majority of SFI and UFI patients. Surgical correction of the anal sphincter was performed after biofeedback failure.