Chronic graft versus host disease (cGvHD) is the most common cause of late morbidity and mortality after allogeneic hematopoietic stem cell transplantation (HSCT). We retrospectively evaluated the impact of NIH classification on outcome of patients at our center. Primary endpoint was overall survival at 5 years. Two hundred one patients with cGVHD according to NIH were included. Platelets <100,000/μl on day of diagnosis of cGvHD (HR 2.97, 95 % CI 1.7-5.3, p < 0.001), female donor (HR 1.78, 95 % CI 1.0-3.2, p = 0.05), and reduced intensity conditioning (HR 1.95, 95 % CI 1.0-3.8, p = 0.05) impacted overall survival. Non-relapse mortality (NRM) was higher for patients with low vs. high platelets: 26 % (95 % CI 14-40) vs. 6 % (95 % CI 2-10), p < 0.001, and tended to be higher for female vs. male donor: 14 % (95 % CI 7-23) vs. 7 % (95 % CI 3-13), p = 0.08. Relapse tended to be higher for recipients of reduced intensity conditioning (RIC) vs. myeloablative conditioning (MAC): 33 % (95 % CI 23-43) vs. 20 % (95 % CI 10-31), p = 0.06. After excluding patients with myeloma and lymphoma, IgG serum levels at diagnosis of cGvHD of 122 patients were correlated with survival. IgG levels above normal were associated with worse 2-year overall survival (OS), p = 0.04, compared to normal or low IgG levels. Platelet count at diagnosis remains the most valid prognostic factor for survival of patients with cGvHD even in the era of NIH grading. High IgG level at diagnosis of cGVHD represents a potential negative prognostic parameter that deserves further investigation.