Background: Tracking expenses may be useful to minimize financial distress in cancer patients. Our objective was to evaluate uptake and satisfaction with an out of pocket (OOP) cost tracker for gynecologic cancer patients on treatment. Methods: Within a longitudinal survey to assess financial burden among gynecologic cancer patients starting a new line of systemic therapy at a tertiary-care cancer center, we provided worksheets for participants to track their OOP expenses voluntarily. We assessed patient usage and satisfaction at 3 and 6 months. Financial distress was measured using Comprehensive Score for Financial Toxicity < 26. Results: Among 121 participants with an average age of 59 years, 34 (28%) were African-American and 33 (27%) had a high school diploma or less. Half (55/110, 50%) of participants reported annual income < $40,000. Most participants had health insurance (113/121, 93%) and were unemployed (77/118, 65%). Forty-nine of 121 (40%) participants reported ever using the OOP cost tracker at 3 or 6 months. Those who used the cost tracker stated it was helpful to track costs (86%, 73%), easy to use (97%, 100%), and useful for budgeting (42%, 24%) at 3 and 6 months. Participants reported using the cost tracker at least weekly (33%, 19%), every 2 weeks (36%, 27%), or monthly (31%, 54%) at 3 and 6 months. Twelve participants returned their OOP cost trackers for review with a median use of 5.5 months (range 3-10). Average monthly patient-reported OOP costs (range) were: $41 ($0-$584) for direct non-medical costs (i.e., transportation, lodging), $15 ($0-$120) for outpatient services, $13 ($0-$150) for medications/supplies, and $9 ($0-$100) for hospital services. Use of the OOP cost tracker at 3 months was not associated with financial distress at baseline (p = 0.30) or at 3 months (p = 0.89). Qualitative analysis showed the OOP cost tracker reminded patients to save receipts and to track categories of cost they would not have otherwise considered. Conclusions: 40% of gynecologic cancer patients undergoing treatment used an OOP cost tracker worksheet and found it helpful and easy to use. Direct non-medical costs accounted for the highest average monthly patient-reported OOP cost.