7072 Background: LG-NHL is mostly incurable, imposing a prolong impact of cancer care burden for pts. This study aimed to quantify the burden of MH conditions in pts with newly diagnosed chronic lymphocytic leukemia/small lymphocytic lymphoma (CLL/SLL), follicular lymphoma (FL), mantle cell lymphoma (MCL), Waldenström macroglobulinemia (WM), or marginal cell lymphoma (MZL). Methods: A retrospective study was conducted using Optum Clinformatics Data Mart to identify pts ≥18 years with ≥1 new diagnosis for CLL, FL, MCL, WM, or MZL from 6/2016-6/2022 (index period). Pts were required to be continuously enrolled for 60 days pre- and 365 days post-index date, defined as the date of first cancer diagnosis. Incidence and prevalence of MH conditions of interest (anxiety, depression, stress reaction/adjustment disorder, insomnia, post-traumatic stress disorder [PTSD]) were categorized based on if diagnoses were post- or pre-index date. All-cause healthcare resource utilization (HCRU) and costs were measured during the 1-yr follow-up period. Results: Approximately half of newly diagnosed 36,054 LG-NHL pts (CLL/SLL=48.0%; FL=52.7%; MCL=57.2%; WM=50.5%; MZL=52.5%) had either an incident (19.4-25.7%) or prevalent (28.6-32.1%) MH condition diagnosis following their cancer diagnosis (Table). There were no significant demographic differences in pts with and without MH conditions. LG-NHL pts suffered most from anxiety (30.9-38.2%) and depression (27.5-31.9%), followed by insomnia (16-23.1%), stress (10.3-13.5%), and PTSD (1.4-1.9%). Median time from cancer diagnosis to onset of a MH condition was 334 days for CLL/SLL, 301 for FL, 248 for MCL, 351 for WM, and 328 for MZL. LG-NHL pts with an identifiable MH diagnosis had significantly higher costs and HCRU compared to those without; for example, in CLL/SLL pts with MH diagnosis, outpatient visits were 1.4 times higher, inpatient admissions 3.0 times higher, and costs 2.1 times higher than those without (all P=0.0001). HCRU and cost increases were also observed in MCL, FL, WM, and MZL pts with MH diagnosis. Conclusions: This real-world study uncovered a high proportion of LG-NHL patients suffer from MH conditions, incurring higher financial burden than those without. With advancements in new treatments, there remains unmet need of MH burden in these pts. [Table: see text]