Our aim was to assess the efficacy of MAS065D, a non-steroidal water-in-oil cream, in preventing and limiting skin reactions caused by radiation therapy (RT). 40 women treated with conservative breast cancer surgery followed by radiotherapy, were randomised to receive MAS065D (22 pts) or vehicle (18 pts). Radiotherapy was delivered in 20 fractions: 2.25 Gy to the whole breast plus a concomitant boost of 0.25 Gy to the tumour bed up to a total dose of 50 Gy. Evaluations of skin toxicity, erythema, and subjective symptoms were carried out weekly and 3 weeks after treatment completion. A statistically significant difference between vehicle and MAS065D groups was recorded regarding the maximum severity of skin toxicity (p < 0.0001), burning within the radiation field (p = 0.039) and desquamation (p = 0.02), in favour of the latter. We conclude that MAS065D may be considered a safe and effective treatment in the prevention and minimization of skin reactions and associated symptoms.