Background: Patients with nonmetastatic NSCLC receiving platinum-based chemotherapy are at an intermediate risk (10-20%) of developing FN; clinical practice guidelines recommend assessing whether these patients have FN risk factors before considering myeloid growth factor (MGF) prophylaxis. Most NSCLC patients receiving chemotherapy have ≥1 FN risk factors, and while PP leads to lower rates of FN across all cycles, it is more costly compared to SP. This study evaluates the cost-effectiveness of PP vs. SP using a biosimilar MGF, filgrastim-sndz, in NSCLC patients at intermediate risk of FN. Methods: A Markov model with a lifetime horizon was constructed to evaluate the total costs and clinical outcomes of using filgrastim-sndz as PP vs. SP in NSCLC patients 61 years old receiving adjuvant carboplatin/paclitaxel every 3 weeks for 4 cycles. Separate analyses were conducted for patients with 0 FN risk factors (0RF) and with ≥1 FN risk factors (1+RF), representing 11.3% and 18% baseline FN risk, respectively. Incremental cost-effectiveness ratios (ICERs) were calculated for cost per FN event avoided, life-year saved (LYS), and quality-adjusted life-year (QALY) gained from a United States payer perspective. Deterministic and probabilistic sensitivity analyses (PSA) were conducted. Results: For patients with 0RF, use of filgrastim-sndz as PP vs. SP provided an additional 0.056 QALYs (0.079 LYS) at an incremental cost of $3,266. The ICERs were $46,815, $41,555, and $58,531 for cost per FN event avoided, cost per LYS, and cost per QALY gained, respectively. For patients with 1+RF, PP vs. SP added 0.090 QALYs (0.127 LYS) at an incremental cost of $1,605. The ICERs were $13,970, $12,644, and $17,805 for cost per FN event avoided, cost per LYS, and cost per QALY gained, respectively. In the PSA, the likelihood of cost-effectiveness at a willingness-to-pay (WTP) threshold of $50,000 per QALY gained was 31.7% for patients with 0RF and 96.6% for 1+RF. Conclusions: For NSCLC patients at intermediate risk of FN receiving adjuvant carboplatin/paclitaxel with 1+RF, PP with filgrastim-sndz compared to SP is cost-effective based on a WTP threshold of $50,000/QALY.