Genome-wide association (GWA) studies are applied to identify novel genetic variants that are associated with disease. Results of the first three GWA studies on asthma identified susceptibility genes for asthma as ORMDL3, IL1RL1, and PDE4D. The first GWA study on chronic obstructive pulmonary disease (COPD) identified two single nucleotide polymorphisms at the alpha-nicotinic acetylcholine receptor (CHRNA 3/5) locus, identified earlier as risk factor for both lung cancer and nicotine dependence, to be associated with COPD. GWA studies have been shown to be relevant study designs that brought us new insight and identified novel genetic factors for asthma and COPD, but future studies should take environmental factors into account and proceed with more in-depth studies on functionality of the identified variants and their impact on public health.