This study was carried out to examine profitability and value addition of maize (Zea mays L.) processing into by-products (such as sweet corn, popcorn, corn flakes, corn meal, corn oil, corn flour e.t.c) based on the methods of processing technology being used in Imo State South-eastern Nigeria. Its specific objectives includes; the socio-economic characteristics of maize processors, source of raw maize as well as disposable of value added products of maize, methods of processing technology used, average costs and returns analysis of processing technology for value added products of maize and its profitability per week, constraints encountered by maize stakeholders. The three agricultural zones were used through the adoption of Questionnaire/interview schedule and also, purposively selected with three stage random sampling technique that give a total of 160 respondents for the study. Data were analyzed using Descriptive Statistics, Value Added/Gross Margin Analysis. The study revealed that maize (Zea mays L.) processing is profitable and has a vital value added concept. Thus, the level of profitability and value addition is higher for processors using Mechanized Processing Technology than those processors using Manual Processing Technology. This is due to reduction in processing cost, high yield of output with great efficiency at limited period of time. In view of its potential for attainment for food security and good standard of living, it is concluded that processors that currently using Manual Processing Technology should be encouraged to shift to Mechanized Processing Technology because it saves time and money that can be put into other economical use. Thus, it was recommended that more Processing centres should be established in each of the agricultural zones of South-eastern Nigeria and processors should have access to credit facilities from bank and international organizations.