Drug-induced liver injury (DILI) is a rare but potentially serious idiosyncratic reaction. By using candidate gene and genome-wide association studies, replicated associations for DILI susceptibility with HLA genes and genes relevant to drug metabolism have been detected, mainly since 2000. The HLA associations include a strong association between flucloxacillin-induced injury and the class I allele B*5701 and weaker associations for co-amoxiclav and ximelagatran DILI with the class II genotype. These associations suggest an injury mechanism involving an immune response, possibly to a complex of drug or metabolite and protein. For genes relevant to drug metabolism, the best replicated association is between isoniazid DILI and NAT2 slow acetylation. Homozygosity for GSTM1 null and/or GSTT1 null alleles also seems to be a risk factor for DILI, with associations described independently for several drugs. Other not-yet-replicated associations have been described for genes relevant to drug metabolism and oxidative stress and cytokine genes.