Previous researches have identified the positive effects of gratitude on happiness and well-being. It has been found that spirituality can enhance gratitude and well-being. Our study aimed to examine the link between gratitude and subjective well-being among religious and non-religious people. Furthermore we tested if a 4-week long gratitude diary has a positive effect on subjective well-being.In our online, qualitative investigation the sample consisted of 54 males and 169 females (mean age=39.13, SD=15.90). 54.1% of respondents regarded themselves as "religious with a given religion", 24.8% as "religious on my own way" and 21.2% as "non-religious". The experimental group (leading a gratitude diary for 4 weeks) with 103 individuals and a control group with 120 individuals with no differences in age, gender and religiousness. We compared the questionnaires' results (filled out both before and after the intervention) of the experimental group (n=103) with the results of the control group (n=120) similarly filled out on two different occasions. We applied Gratitude Resentment and Appreciation Test and Subjective Well-being Scale.Our results showed that religious people showed elevated level of gratitude (F(2, 219)=23.66, p<0.001) but same well-being (F(2, 219)=1.97, p=0.142) compared to non-religious groups. In the experiment group the gratitude and the subjective well-being both increased (p<0.01), and there was no significant changes in control group. 2x2 ANOVA showed significant interaction effect (Subjective well-being: (F(1, 221)=13.32, p<0.001); Gratitude: F(1, 221)=12.43, p<0.001).Religiousness is linked to higher gratitude and an increase in gratitude can result in an increase in subjective well-being. The importance of gratitude diary both among religious and non-religious people will be discussed.