Objective: To determine the rate, maternal characteristics, timing, and indicators of severe maternal morbidity (SMM) that occurs at postpartum readmission. Study design: Women with a birth in California during 2008–2012 were included in the analysis. Readmissions up to 42 days after delivery were investigated. SMM was defined as presence of any of the 21 indicators defined by ICD-9 codes. Results: Among 2,413,943 women with a birth, SMM at readmission occurred in 4229 women. Of all SMM, 12.1% occurred at readmission. Over half (53.5%) of the readmissions with SMM occurred within the first week after delivery hospitalization. The most common indicators of SMM were blood transfusion, sepsis, and pulmonary edema/acute heart failure. Conclusion: Twelve percent of SMM was identified at readmission with the majority occurring within 1 week after discharge from delivery hospitalization. Because early readmission may reflect lack of discharge readiness, there may be opportunities to improve care.