In order to elucidate the factors which have influence on the prognosis of aphasia, correlation between recovery rate of aphasia and the five factors, i.e. initial evaluation of speech test, age, educational level, time between onset and institution of therapy and size of abnormal findings in CT (computed tomography), was studied in 76 right-handed aphasic patients, using multivariate analysis. Cluster analysis and factor analysis were used for analysis of five factors and multiple regression analysis was used for estimation of recovery rate of aphasia. The method of calculation of recovery rate of aphasia is the same to our previous report. The results obtained were as follows: As to analysis of factors, first similarity group among initial evaluation of speech test, recovery rate of aphasia and educational level and second similarity group among time between onset and institution of therapy, size of abnormal findings in CT and age were observed. As to the estimation of recovery rate of aphasia, multiple correlation coefficient of regression analysis using five factors were 0.758, 0.444, 0.627, 0.620, 0.810 and 0.375 respectively in total score, hearing, speaking, reading, writing and calculation on standard language test of aphasia. As to the weight or partial correlation coefficient of regression analysis to the five factors, initial evaluation of speech test, time between onset and institution of therapy and educational level were 129.46, -49.93 and 45.65 respectively and the one of the size of abnormal findings in CT was not high. Stepwise multiple regression analysis of five factors were made.(ABSTRACT TRUNCATED AT 250 WORDS)