Background: Chemotherapy-induced peripheral neuropathy (CIPN) is a common side effect that manifests in the hands or feet primarily as numbness or tingling but can also have motor or painful components. CIPN monitoring is typically conducted by patients self-reporting symptoms during appointments or via questionnaires. Objective CIPN testing may improve early detection but is not typical during treatment, perhaps due to the need for specialized equipment and personnel. The objective of this pilot study was to conduct initial testing of a smartphone app that collects patient-reported and objective CIPN data. Methods: NeuroDetect V1.0 (available in iOS app store) includes a patient-reported CIPN questionnaire (EORTC CIPN20) and two functional assessments available within ResearchKit, the Gat and Balance and 9-Hole Peg tests. Patients who had completed neurotoxic chemotherapy were enrolled to complete NeuroDetect assessments one time. Study participants were classified as CIPN cases if they answered ≥ 3 for at least one of the first four CIPN20 questions, which ask about numbness or tingling in the hands or feet on a 1-4 scale. User acceleration data features were extracted with two open source tools, mhealthtools and pdkit. The results of the functional assessments were compared between CIPN cases and controls in principal component analysis and partial least squares discriminant analysis. Results: Twenty-four patients who had completed neurotoxic chemotherapy enrolled and completed the NeuroDetect assessments. Integration across all 87 features measured in the gait and balance test explained 42% of the difference between CIPN cases (n = 14) and controls (n = 10) and 9 individual features were significantly different between cases and controls (all p < 0.05). In the 9-hole Peg Test, hand speed explained 77% of the difference between CIPN cases and controls. CIPN cases took longer to complete the 9-hole peg test though the difference was not statistically significant (dominant hand mean 407.3 vs. 406.2 ms, p = 0.075). Conclusions: App-based functional assessment may detect evidence of CIPN. We are developing additional CIPN functional assessments for NeuroDetect V2.0 to test CIPN detection in a longitudinal study of patients undergoing neurotoxic chemotherapy.