Green buildings may become the solution to the problem of high energy consumption, including those that are subject to verification by the relevant institutions issuing green certificates. The aim of the paper is an analysis and a brief discussion of trends related to the certification of office buildings in Poland. At the end of 2017, almost 9.7 million m2 of modern office space was available in Poland, of which 62% was a certified area. This constitutes a five percent increase in the share of certified office space in relation to the total modern office space available during 2017. In order to compare the costs and benefits of certified buildings, the costs of an office building and a certified building were simulated. The comparison was made using the idea of costs in the life cycle and calculating the Life Cycle Cost. The difference between the base building and the green one was mainly based on obtaining higher Net Present Value with lower investment expenditures for the green building. There was also a clear difference between the beginning of investment profitability for the different levels of rent.