There are no doubts regarding the fact that the subject sustainability has gained a lot of attention and importance to the public over the past years. Everything from ecological products to electric cars and fair working environment shows us that everyone can gain something from working with sustainability, even the companies. The fact is that with all the coverage in media about how companies working with sustainability increase their profitability it has almost become public knowledge. Whether there are facts to back this claim is however not certain. The research that has been done shows not only a positive relationship between a company’s work with sustainability, also called CSR, and their profitability, but also a negative and a neutral relationship. This paper aimed to give some clarity in the issue; using theories for signaling, legitimacy, and stakeholders, three hypotheses were formed to answer the question of whether there is a relationship between CSR and firm profitability for companies in the EU-countries and how the increased demands for sustainability and sustainability reporting has affected that relationship over time. Through a longitudinal study using the tools correlation and t-test several results were received, these mainly highlights the fact that as the demands and regulations for sustainability has increased the companies’ performance regarding sustainability has increased at the same rate. The results also reveal a neutral relationship between CSR and firm profitability. Furthermore, the study indicates a change in the relationship over time; from slightly negative to slightly positive. This result however isn’t statistically significant and requires extended research.