The systemic effects of acute experimental tuberculosis as reflected by alterations in the concentration and distribution of the proteins and protein-bound carbohydrates of serum were investigated by filter paper electrophoresis. Electrophoretic analyses were performed on serum samples from groups of adult, female guinea pigs sacrificed 8, 15, 19, 29, and 50 days following innoculation with 0.1 mg Mycobacterium tuberculosis. Significant increases occurred in total serum glycoprotein levels and in the protein component of the [alpha]1 -globulin fraction 8 days post-infection. A marked elevation of the polysaccharide moiety of the [alpha]2-globulin fraction and a significant decline in albumin protein was observed 15 days following infection. With the exception of significant increases in the components of the gamma-globulin fraction in the latter stages of the study, major alterations in the other subtractions of serum had occurred by 15 days post-infection. It is suggested that the early alterations in the electrophoretic patterns represent primarily systemic manifestations of the inflammatory response.