Police are said to be hunting up to three assailants after what they suspect is a settling of scores in a gangland feud.
But sources close to the investigation report that the victim, whose identity has not been made public, may not have been the intended target, according to local newspaper Diario de Mallorca.
He was shot four times in the back outside an empty supermarket in Costa de la Calma, a popular resort around 25km from the island's capital Palma.
He was walking group of friends that included his wife down Santa Ponça, the main shopping street in the resort on the west of the island, when a hooded man ran by and fired four shots.
Attempts by paramedics to revive him at the scene failed.
The Costa del Sol and Ireland has been rocked by a series of tit-for-tat killings blamed on a gangland feud between the Kinahan and Hutch families.