Hodgkin/Reed-Sternberg (HRS) cells in the setting of chronic lymphocytic leukemia (CLL) exist in two forms: type I with isolated HRS cells in a CLL background (Hodgkin-like lesion), and type II with typical classic Hodgkin lymphoma (CHL), a variant of Richter transformation (CHL-RT). The clinical significance of the two morphological patterns is unclear, and their biological features have not been compared. We retrospectively reviewed 77 cases: 26 of type I and 51 of type II CHL-RT; 3 cases progressed from type I to type II. We examined clinical features, EBV status, and clonal relatedness after microdissection. Median age for type I was 62 years vs. 73 years for type II (p=0.01). 27% (type I) vs. 73% (type II) had a history of CLL. HRS cells were positive for EBV in 71% (55/77), similar in type I and II. Clonality analysis was performed in 33 cases (type I and type II combined): HRS cells were clonally related to the underlying CLL in 14 and unrelated in 19. ZAP-70 expression of the CLL cells, but not EBV status or morphological pattern was correlated with clonal relatedness: all 14 clonally related cases were ZAP-70-negative while 74% (14/19) of clonally unrelated cases were ZAP-70-positive. Overall median survival (types I and II) after diagnosis was 44 months. Advanced age was an adverse risk factor for survival, but not histological pattern, type I vs type II. HRS-like cells in a background of CLL carries a similar clinical risk to that of CHL-RT, and may progress to CHL in some cases.