According to current literature and preliminary data, hydroxychloroquine (HCQ) seems potentially effective in the treatment of patients with Covid-19 pneumonia. The concentrations of HCQ in lungs might be well above that of plasma. Most likely, this property of HCQ provides effective drug concentrations in lungs. HCQ has a gradual onset of action in the treatment of rheumatic diseases. This could be valid for the treatment of Covid-19 pneumonia. It was suggested that regular HCQ administration in animals for a certain time might result in gradual accumulation of HCQ in tissues. Reduced perfusion, somewhat distorted architecture of lung tissue, edema and, suggested gradual accumulation of HCQ in lung tissue might cause reduced HCQ concentrations in pneumonic areas of the lungs in Covid-19 pneumonia. Patients with Covid-19 pneumonia and extensive lung involvement might have less HCQ concentrations in their lungs than patients having limited lung involvement. Furthermore, patients with Covid-19 pneumonia and extensive lung involvement might have more viral load than patients having limited lung involvement. That’s why treatment of patients with advanced Covid-19 pneumonia using HCQ might result in treatment failure, however HCQ might be effective in the treatment of patients with mild and moderate Covid-19 pneumonia. Using HCQ in Covid-19 pneumonia prophylaxis seems logical since providing enough accumulation of HCQ in the healthy lungs, before the arrival of the SARS-CoV-2 virus, might prevent Covid-19 pneumonia. However, the purpose of this paper is not to recommend using or not using HCQ for the treatment or for the prophylaxis of Covid-19 pneumonia. The purpose of this paper is only to try to bring a new perspective on the role of HCQ in the treatment or in the prophylaxis of Covid-19 pneumonia. This paper proposes only hypotheses, which need further researches to be confirmed.