OBJECTIVES: To examine the cellularity and thickness of the articular cartilage of the femur in rats with arthritis after treatment with iontophoresis. METHODS: To evaluate these objectives, a histological analysis was performed on hematoxylin and eosin, where cellularity and cartilage thickness were observed and evaluated qualitatively and quantitatively by manual counting by 700.09µm² area. RESULTS: The group treated with IAA had normal cellularity (40.1 cells/μm2) and maintenance of non-calcified cartilage (75.5μm), suggesting normal thickness. The non-treated group C+, on the other hand, had a lower mean number of chondrocytes (13.0μm2) (P <0.05) and, when the cartilage thickness was compared, it showed higher average thickness of calcified cartilage (104.8 mm) and lower mean of non-calcified cartilage (53.3μm) CONCLUSION: The use of iontophoresis with L-ascorbic acid by continuous electric current contributed to a quantitative gain of chondrocytes and improved the thickness distribution of calcified and non-calcified cartilage. Level of Evidence III, Case Control Study.Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)