Here we present a microfluidic method for the analysis of single cell secretions. The method co-encapsulates cells with microspheres conjugated with capture antibodies and detection fluorescence labeled antibodies. The secreted substance captured on the microsphere surface and detected via detection antibodies generating a localized fluorescent signal on a microsphere surface. Using this method, CD4+CD25+ regulatory T cells were encapsulated and assayed to detect individual IL-10 secreting cells in population.