Refrigeration is, and has been an essential component of marine engineering practice for the past several decades, however, with increasing worldwide awareness of the detrimental effects refrigerants can have on the environment, this “niche” area of the marine engineering profession has undergone major regulatory changes. This article lists the regulatory changes with their enforcement and phase-out date for the most commonly used marine refrigerants, proposes suitable environmentally acceptable alternatives detailing their performance evaluation, and describes the most common problems encountered during the conversion process for existing marine HVAC and provision refrigeration installations both in the off-shore sector and on ocean-going vessels based on statistical data and practical real-world examples witnessed by me in my professional practice