The purposes of this research were to study nonformal education needs for vocational development of the employees working in yarn industrial factories in Samut Prakan province conderning knowledge in three aspects as follows : the aspect of general nonformal education, vocational skills training and information service classified by sex, age, education level, work experiences, factories size and type The sample used in this research were 334 employees in yarn industrial factories. The statistics used for analyzing data were percentage, mean, standard deviation, t-test, F-test and scheffes method. The significant research findings were as follows: 1. The employees with different sexes working in yarn industrial factories had no significantly statistical difference in nonformal education needs for vocational development as a whole but had significantly statistical difference at the .05 level in the particular aspect of general nonformal education. 2. The employees with different ages working in yarn industrial factories had no significantly statistical difference in nonformal education needs for vocational development as a whole but had significantly statistical difference at eht .05 level in the particular aspect of general nonformal education. 3. The employees with different education levels working in yarn industrial factories had significantly statistical difference at the .05 level in nonformal education needs for vocational development as a whole as well as in the particular aspect of general nonformal education. 4. The employees with different work experiences working in yarn industrial factories had no significatly statistical difference in nonformal education needs for vocational development as a whole but had significantly statistical difference at the .05 level in the particular aspect of general nonformal education. 5. The employees working in different sizes of yarn industrial factories had no significantly statistical difference in nonformal education needs for vocational development as a whoe but had significantly statistical difference at the .05 level in the particular aspect of general nonformal education. 6. The employees working in different types of yarn industrial factories had no significantly statistical difference in nonformal education needs for vocational development as a whole as well as in all aspects.