A total of 1,220 subjects from Equatorial Guinea living in Spain (median age = 41 years; 453 male and 767 female) was examined for antibodies to human immunodeficiency virus (HIV) and Hepatitis B (HBV), C (HCV), and D (HDV) viruses. Extracted RNA and DNA from the positive samples were used to quantify viral load. The prevalence of HIV antibodies, HCV RNA, and HBV surface antigen (HBsAg) was 10.8% (N = 132), 11.6% (N = 141), and 7.9% (N = 96), respectively. The most prevalent HIV variant was CRF02_AG (38.5%; N = 40). HCV genotype 4 (60%; N = 36) and HBV genotype A3 (32%; N = 8) were the hepatitis variants most frequently found. Superinfection with HDV was seen in 20.9% (N = 24) of HBsAg carriers. A control group of 276 immigrants from other sub-Saharan countries showed similar rates of HIV and HBsAg, although no HCV cases were found. Immigrants constitute a major source of HIV and hepatitis viruses in Spain; therefore, it is important that control measures are intensified.