Long and short acting β2-mimetics are essential in  asthma treatment. Effects of treatment, side effects including even increase of mortality rate, differ amongst patients  using those drugs. Many researchers suspect that genetic disorders are the most likely reasons of those findings. Genetic studies have focused mainly on single nucleotide polymorphisms (SNP) in β2-mimetics receptor gene (ADRB2). ADRB2 is located on the long arm of chromosome 5 (5q31-33). Gly16Arg and Gln27Glu are the most common SNP in clinical studies. Patients with 16Arg/Arg variants using SABA as rescue therapy have developed better response to asthma treatment. Studies with SABA administrated regularly have shown much worse asthma control. 16 Arg/Arg patients during LABA therapy had worse pulmonary function parameters and more frequent asthma exacerbations. It is very important that other studies haven’t confirmed those outcomes. We need further research to clarify all those issues.  Their findings may lead to more individualised therapy which allow to adjust particular drugs and their doses to particular patients.