In books and articles such as “Software Engineering: A Practitioner's Approach” (Pressman R. S., 2008), Software Engineering (Sommervile, 2011), which since the 70s, have been talking about the issue of software maintenance, placing it among the 67 % and 90% of the total cost of the life cycle of the development of an information system. Despite the efforts of these and other scholars, few investigations or production of data on the subject are reported. Today, software maintenance is one of the most necessary and important processes for companies, but, simultaneously, one of the most complicated and costly, so, in the present work, a methodological guide is proposed that has been called Mantelasoft, focused on the process of evolution and maintenance of software, specifically for MSMEs and software development departments, which corresponds to a combination between the Agil Mantema process and the support processes proposed by ISO / IEC 12207: 2008, which includes a model with phases, activities, metrics and techniques. Where in the first phase data is collected, through a survey and a focus group of entrepreneurs, on how some Pereira companies perform software maintenance on their products. After analyzing the information obtained and reviewing existing software maintenance guides, Mantelasoft is generated and proposed. Finally, Mantelasoft is applied in two companies in Pereira, where before and after the application an evaluation is made of the software maintenance performed there, to later know the strengths and points to improve of Mantelasoft.