Metabolic analyzers are standard tools in research-based, exercise physiology laboratories in university settings. Portable, low-cost metabolic analyzers have the capacity to extend the value of metabolic gas analysis beyond the traditional laboratory setting. PURPOSE: This study’s purpose was to assess validity and reliability of a portable, low-cost metabolic analyzer (VPRO) for assessment of oxygen consumption (VO2) and minute ventilation (VE) during progressive cycling testing. METHODS: In Protocol 1, eight male participants (height: 171.9 ± 5.8 cm, weight: 79.6 ± 8.3 kg, age: 41.0 ± 12.3 years) with previous competitive cycling experience ranging from 2-40 years completed an hour-long stationary cycling protocol twice, progressing from 100-300 Watts every 10-12 minutes while wearing the VPRO and a criterion measure (PMED) for five minutes each, at each stage. In Protocol 2, 16 recreationally active male participants (height: 168.2 ± 8.4 cm, weight: 76.5 ± 13.3 kg, age: 23.0 ± 9.4 years) completed three incremental, maximal stationary cycling tests wearing one of three analyzers for each test (VPRO version 1.1.1, VPRO version 1.2.1, PMED). Mean absolute percent differences (MAPD) ≤10% were deemed acceptable validity/reliability. RESULTS: For Protocol 1 and convergent validity, the VPRO had mean absolute differences from the PMED of <0.3 L/min for absolute VO2 and <5 L/min for VE overall and at each exercise stage. MAPD for VO2 and VE were <9% overall and <12% at each exercise stage. Test-retest reliability of VO2 and VE of the VPRO (MAPD: 8.9-11.0%) was lower than the PMED (MAPD: 4.7-7.6%). For Protocol 2, validity was similar for both VPRO versions (MAPD ~12% overall) compared to the PMED for VO2 and VE. CONCLUSIONS: The VPRO had an acceptable validity and test-retest reliability for most variables and intensities tested and may be an appealing option for VO2 and VE analysis.