[1] In 1972 she represented her country in the first edition of the OTI Festival which was held in Madrid, in which she won the fourth place.
Three years later she was again internally selected by Venevision to represent Venezuela in the fourth edition OTI Festival which was held in San Juan, Puerto Rico.
Castellanos has taken part, almost every year, in musical presentations for the annual contest Miss Venezuela, produced by Joaquín Riviera.
The use of expensive costumes and sparkling choreographies were aspects well managed by Mirla during the "golden years" of Venezuelan television.
Currently, Mirla Castellanos is a respected singer with many awards and international recognition in the Spanish speaking countries and markets for "Balada romántica" (romantic and popular Hispanic music).