To examine the effects of different forms of questionnaire items (Yes-No type vs. Yes-?-No type and affirmative statement vs. question statement), on factorial validity, a total of 360 extension items were prepared based upon the present 16 P.F. test. These 360 extension items and the 16 P.F. forms A, B, and C were administered to 218 college students. After confirmation of the existence of 16 personality factors as defined in the 16 P.F. test, the correlations were obtained between the estimated factor scores and the answers to the 360 extension items. The 2 X 2 factorial design (i.e. 2 answer types and 2 question types)' was considered for each of the fifteen factors, excluding factor B, and the analysis of variance was made for each. The results showed that only for factors A and Q3 was there significance of interaction (question type and answer type). It was concluded that item forms iii the questionnaire do not affect the factorial validity.