The present paper analyses the productivity growth pattern in the urban informal manufacturing sector of Assam; an underdeveloped state of India, which has the potentialities of becoming the manufacturing hub of the north eastern part of India, as it is industrially the most developed state in this part of the nation. The productivity of the UIMS of the state is calculated and compared to the national average by using both partial and total factor productivity measures. The gross value added is used as a measure of output, which is deflated by the wholesale price index for the manufactured products. Capital input is represented by the gross fixed assets, which is deflated by the wholesale price index for the machine and machinery tools. Total factor productivity growth in this study is taken as the difference between the growth rate in value added and a weighted sum of capital, and labour growth rates, the weights being the share of labour and capital in value added respectively. The index of efficiency of labour has been computed for the state and compared to the national levels. The index is calculated as the difference between the actual growth rate of labour productivity and the desired growth rate of labour productivity. The study finds that the productivity per enterprise and labour productivity is higher and capital productivity is lower in the informal manufacturing sector of Assam as compared to the all India level. The positive total factor productivity growth of this sector both at the national as well as at the national level is an encouraging signal for the development of this sector not only in Assam but for the nation as a whole.