The present study examined outcomes on the Tennessee Comprehensive Assessment Program/Achievement Test (TCAP/AT) for the KIPP:DIAMOND Academy (KIPP:DA), which is in its second year of operation. Importantly, as in Year 1, a rigorous quasi-experimental research design was employed, in which each KIPP:DA student was individually matched to a highly similar counterpart who attended one of several geographically proximate neighborhood schools. The 2004 TCAP/AT was taken by three subsamples of KIPP:DA students: (a) fifth graders who had completed their first year at the school, (b) sixth graders who had also completed their first year, and (c) sixth graders who had completed their second year at the school. "Pretest" analyses revealed that KIPP:DA and control students scored almost identically on the TCAP/AT in the year prior to the former group's enrollment in KIPP:DA. Comparisons between the three KIPP:DA groups and their matched control counterparts on each of the TCAP/AT subtests (Reading, Language Arts, Mathematics), directionally favored KIPP:DA in 7 out of the 9 analyses (median ES = +0.14) unadjusted for pretest score, and in 8 out of 9 analyses (median ES = +0.16) adjusted for pretest scores. Inferential analyses showed the KIPP:DA advantages to be statistically significant for only the fifth-grade and sixth-grade longitudinal cohort subsamples. Supplementary descriptive analyses of the criterion-referenced (CRT) portion of TCAP/AT further revealed that, while not statistically significant, KIPP:DA students in all three subsamples were more frequently represented than the matched control students at the Proficient and Advanced levels, and less frequently at the Below Proficient level, in both Reading/Language Arts and Mathematics. These results are clearly suggestive of positive KIPP:DA effects in Year 2, especially in view of the doubling of school size and special unanticipated challenges faced during the year. Pretest School Attendance for Control Group Mates tabular data is appended. (Contains 4 tables.)