We have previously reported that lymphoid cells from systemic lupus erythematosus (SLE) mice with established disease migrate aberrantly.1This study evaluates the abnormal lymphocyte migration patterns found in MRL-lpr/lpr (MRL/1) mice in relation to age, disease manifestations and the expression of lymphocyte homing receptors,51chromium-labelled lymph node cells from MRL/1 and from normal histocompatible CBA mice of different ages were injected i.v. into age and sex-matched CBA recipients. Diminished lymph node and increased hepatic uptake of MRL/1 compared to CBA cells was evident as early as 6 weeks of age. Abnormalities in lymphocyte migration antedated the appearance of elevated antihistone antibody (AHA) levels but not the development of lymphadenopathy. Using the monoclonal antibody MEL-14, no differences in the expression of lymphocyte homing receptors between MRL/1 and CBA lymph node cells were found at any age. Thus abnormalities in lymphocyte migration in MRL/1 mice appear as early as six weeks and are not related to changes in homing receptor expression.