In this paper, we investigate the prevalence rate of smoking in COVID-19 patients and examine whether there is a difference in the distribution of smokers between the two statistical populations of critically ill COVID-19 patients and the entire Iranian population or not. To do this, we first prepared a sample of 300 COVID-19 patients admitted to hospitals in Tehran and Rasht. Then, through the non-parametric statistical runs test, we show that the sample was randomly selected and it is possible to generalize the result of tests on the sample to the community of hospitalized COVID-19 patients. In continuation, we examined the hypothesis that the prevalence of smoking among COVID-19 patients admitted to hospitals is equal to the prevalence rate of smoking in the whole Iranian society. For this purpose, we used the non-parametric chi-square test and it was observed that this hypothesis is rejected. The data show that there is a significant difference in the prevalence of smoking between critically ill COVID-19 patients and the whole of Iranian society. Also, it can be concluded that, the prevalence rate of smoking among COVID-19 hospitalized patients is lower than this rate in the whole Iranian society. The above results show the need for serious research in this field and confirm that while avoiding any positive or negative tendency towards smoking, the causes and factors affecting this phenomenon should be investigated and drugs can be prepared and produced accordingly.