We examined the impact of the Integrated Management of Childhood Illness (IMCI) strategy on the equality of health outcomes and access across socioeconomic gradients in rural Tanzania, by comparing changes in inequities between 1999 and 2002 in two districts with IMCI (Morogoro Rural and Rufiji) and two without (Kilombero and Ulanga). Equity differentials for six child health indicators (underweight, stunting, measles immunization, access to treated and untreated nets, treatment of fever with antimalarial) improved significantly in IMCI districts compared with comparison districts (p<0.05), while four indicators (wasting, DPT coverage, caretakers' knowledge of danger signs and appropriate careseeking) improved significantly in comparison districts compared with IMCI districts (p<0.05). The largest improvements were observed for stunting among children between 24-59 months of age. The concentration index improved from -0.102 in 1999 to -0.032 in 2002 for IMCI, while it remained almost unchanged -0.122 to -0.133 in comparison districts. IMCI was associated with improved equity for measles vaccine coverage, whereas the opposite was observed for DPT antigens. This study has shown how equity assessments can be incorporated in impact evaluation at relatively little additional cost, and how this may point to specific interventions that need to be reinforced. The introduction of IMCI led to improvements in child health that did not occur at the expense of equity.