Long considered to be just a drive-by town for drivers who were going from San Juan to the Eastern area of Puerto Rico, Guaynabo went through a large economical revitalization in the 1980s, under mayor Alejandro Junior Cruz.
With Cruz at the helm, many shopping strips and malls were built, as well as Mario Morales coliseum (then called Mets Pavillion). In addition, many manufacturing plants such as Hanes' plant set foot in Guaynabo then. Guaynabo has, at different times, being voted the most pintoresque and cleanest town in Puerto Rico.
Mayor Cruz died in the early 1990s, and Hector O' Neill became his successor at the mayor's office. Under O' Neill, Guaynabo has continued to grow economically.
Guaynabo's BSN team, the Guaynabo Mets, won national championships in 1980, 1982 and 1989, commanded by the player after whom the coliseum was named, and his brother in law Federico Fico Lopez.