Background: Bipolar Affective Disorder and Schizophrenia are two severe psychotic conditions associated with a high degree of disability depending on their severity. These two conditions can appear to mimic each other as they share some characteristic features. Disability limits the opportunity for these patients efforts to society building, thus knowing their level of disability will assist in the formulation of treatment plans aimed at minimizing the impact of the disorder and improving the functioning of affected patients. Objectives: The present study was designed to compare the level of disability between stable patients with Bipolar Affective Disorder and Schizophrenia attending Federal Neuropsychiatric Hospital, Yaba, Lagos. Methodology: A total of 200 subjects were recruited (100 Bipolar, 100 Schizophrenia). Consecutive outpatient clinic attendees who met the inclusion criteria were selected. All the subjects had their diagnosis confirmed using SCID-P after which a socio-demographic questionnaire was administered on them. Young Mania Rating Scale and Hamilton Depression Rating Scale were administered on bipolar subjects while participants with schizophrenia were assessed with Brief Psychiatric Rating Scale. All the participants were administered the 36-item WHODAS II. The data were analysed with the Statistical Package for Social Sciences, 17th edition (SPSS-17). Results: The socio-demographic factors significantly associated with level of disability in the two groups combined were: employment status (p<0.001), source of income (p<0.001), xv income per month (p= 0.021) and amount spent on treatment (p=0.048). However, level of disability in participants with Bipolar Disorder determined by a mean WHODAS score of 24.93 was associated significantly with marital status(p=0.047), employment status(p=0.023) and source of income (p=0.005). The level of disability in participants with schizophrenia determined by a mean WHODAS score of 27.02 was significantly associated with age group (p=0.007), number of children (p= 0.033), employment status (p=0.003), source of income (p=0.034), amount spent on treatment (p<0.001) and age (p=0.022). The participants with schizophrenia were more likely than those with bipolar to score more in four domains of the WHODAS-II between the two groups viz: self- care (p<0.001), getting along with others (p<0.001), life activities (p<0.001) and participation in the society (p<0.001). In both groups of participants, there were more single participants than married, and unemployed than employed. Both HDRS and BPRS were significantly associated with level of disability using the cut off WHODAS scores in bipolar disorder and schizophrenia respectively (p<0.001). Conclusion: The level of disability in Bipolar Affective Disorder was less than that in Schizophrenia and the single and unemployed participants were more disabled.