BACKGROUND AND OBJECTIVES: Interferential current is widely used in clinical practice for the treatment of low back pain, but there is no literature consensus regarding its parameters. The objective of this study was to analyze the immediate effect of the 2KHz interferential current in chronic low back pain. METHODS: This randomized controlled clinical trial was previously approved by the Research Ethics Committee of the Federal University of Paraná, with the participation of 105 individuals with chronic low back pain (>12 weeks) of both genders. Participants were randomized in 3 groups: placebo group (PG, n=35), electrical stimulus off; interferential current1 (IG1, n=35), carrier frequency 2KHz, AMF of 2Hz, motor intensity level and IG2, n=35, carrier frequency 2KHz, AMF of 100Hz, sensory intensity level. All groups were subjected to a single application for 30 minutes with 4 electrodes in a crossed-shape position in the lumbar region. RESULTS: The visual analog scale, McGill pain scale, Oswestry Low Back disability questionnaire, Roland Morris disability questionnaire and Algometria of pressure were used for evaluation and revaluation. CONCLUSION: It may be noticed that by the visual analog scale and questionnaires, the interferential current provided an immediate analgesic effect in chronic lumbar pain regardless of the mode of stimulation.