Thirty-five patients with primary or secondary immunoglobulin deficiency were included in a crossover study to test the tolerance, clinical efficacy, and safety of a liquid pasteurized 10% concentrated intravenous gammaglobulin versus a 5% concentrated presentation. No statistically significant differences were found between these parameters. Total serum immunoglobulin-(Ig)G and IgG subclass levels were similar in both groups. No modifications in serum alanine transferase (ALT) levels and viral status (HBsAg, HCV-RNA, p24 antigen or RNA for HIV) were observed throughout treatment. Adverse reactions were reported in 3 out of 70 infusions (4.3%), 2 in the experimental group and 1 in the control group. The maximum recommended rate of infusion for the 10% gammaglobulin is the same as for the 5% gammaglobulin product (0.04 ml/kg/min); generally speaking, this means that infusion time is halved. We conclude that a 10% gammaglobulin product is a well-tolerated, clinically efficacious and safe intravenous preparation, and that it could be a short infusion time alternative for primary and secondary antibody deficiencies.