Constraint-induced aphasia therapy (CIAT) has been widely applied as post-stroke aphasia rehabilitation to encourage intensive verbal practice with supported verbal cuing instead of previous habitual compensatory strategies (Pulvermuller et al., 2001). However, this therapy has not yet been reported in Japan; thus, we applied intensive CIAT training to three of our patients with chronic aphasia. Patient 1: aged 72 years, female, three years after onset of Broca aphasia. Patient 2: aged 67 years, male, two years after onset of transcortical aphasia. Patient 3: aged 52 years, female, two years after onset of anomia. The CIAT-II protocol (Johnson et al., 2015) was modified as the Japanese version, which consisted of intensive training using five expressive language exercises and methods of Shaping and Transfer Package for 5 × 3-h weekly sessions for 3 weeks. The Japanese version of the Aphasia Quotient (AQ) in the Western aphasia battery and the Amount Scale (AS) of the Verbal Activity Log (VAL) were also modified to assess aphasia before and after the protocol. The AS improved from 2.7 to 4.6, from 1.4 to 2.8, and from 2.2 to 3.8 in patients 1, 2, and 3, respectively. The AQ did not greatly change in any patient (from 70.8 to 72, from 70 to 73.1, and from 85.9 to 93.7, respectively). The results indicated that the CIAT could improve aphasia assessed by the AS, which was consistent with previous study of CIAT (Johnson et al., 2015) and constraint-induced movement therapy (Taub et al., 2013). The Japanese version of CIAT might be effective as speech therapy for Japanese patients with chronic aphasia.