Introduction Crohn's disease (CD) follows a relapsing and remitting course incurring cumulative bowel damage over time. The question of whether or not the timing of the initiating biologic therapy affects long-term disease progression remains unanswered. Herein, we calculated rates of change in the Lemann index-which quantifies accumulated bowel damage-as a function of the time between the disease onset and initiation of biologic therapy. We aimed to explore the impact of the earlier introduction of biologics on the rate of progression of long-term cumulative bowel damage. Methods Medical records of CD patients treated during 2009-2014 at The Mount Sinai Hospital were queried. Inclusion criteria were two comprehensive assessments allowing calculation of the index at t(1) and t(2): two time-points >= 1 year apart. Patients with biologics introduced before or within 3 months at inclusion (t(1)) were defined as Bio-pre-t(1) and those who did not as Bio-post-t(1). The rate of disease progression was calculated as the change in the index per year during t(1)-t(2). Results A total of 88 patients were studied: 58 Bio-pre-t(1) and 30 Bio-post-t(1). Among the 58 Bio-pre-t(1) cases, damage progressed in 29 (50%), regressed in 20 (34.5%), and stabilized in 9 (15.5%). Median time to initiation of biologics among patients whose index improved was nominally shorter compared to that in patients whose index progressed (8 vs. 15 years). Earlier introduction of biologics tended to correlate with the slower rate of progression (rho = 0.241; p = 0.069). Conclusions Earlier introduction of biologics tended to correlate with the slower progression of bowel damage in CD, reflected by the reduced rate of Lemann index progression.