This interpretive study provides a cross-case analysis of the literacy instruction of two first-grade teachers, with a particular focus on their grouping practices. One key finding was the way in which these teachers drew upon a district-advocated approach for instruction--an approach to guided reading articulated by Fountas and Pinnell (1996) in which students are instructed in small groups based on reading level--as a resource for their sense-making. Analysis indicated that the two teachers enacted the practice in distinct ways based on their experiences and personal characteristics. Findings further suggested that, reminiscent of research on ability groups conducted mainly in the 1970s and 1980s, instruction and materials in both classrooms were qualitatively different between lower groups and higher groups. Although we do not implicate the practice of guided reading per se, we call for closer examinations of modern manifestations of ability-grouped practices and explorations of alternatives to such practices. (Contains 1 table.)