We aimed to investigate the role of bone marrow infiltration pattern (BMIP) and bone marrow reticulin fibrosis (BMRF) in determining treatment demand in patients with diagnosis of chronic lymphocytic leukemia (CLL). We retrospectively evaluated the data of 65 patients, who were followed with the diagnosis of CLL at Istanbul Training and Research Hospital, Department of Hematology, between July 2007 and June 2016. The median age of the patients was 64 years (range, 32-83). Twenty-three (35.4%) patients were female, and 42 (64.6%) were male. Early/mild grade BMRF was observed in 46 (70.8%) patients and advanced grade BMRF in 19 (29.2%) patients. Eleven (23.9%) of 46 patients with early/mild grade BMRF and 10 (52.9%) of 19 patients with advanced grade BMRF required treatment during follow-up (p = 0.04). According to the BMIP, 14 (21.5%) patients had diffuse and 51 (78.5%) patients had non-diffuse BMIP. Eleven (78.6%) of 14 patients with diffuse BMIP and 10 (19.6%) of 51 patients with non-diffuse BMIP required treatment during follow-up (p < 0.001). In univariate analysis, both advanced grade BMRF and diffuse BMIP had an impact on occurrence of treatment demand (p = 0.028, HR = 3.535 vs. p < 0.01 HR = 15.033). Multivariate analysis also revealed diffuse BMIP to be effective (p < 0.001, HR 13.089), while advanced grade BMRF failed to significantly influence treatment demand (p = 0.140, HR 2.664). In conclusion, in the light of our findings, it is reasonable to consider that bone marrow biopsy at the time of diagnosis might provide a preliminary information about treatment demand in patients with CLL.