The aim of the present study was to evaluate the in vitro interactions of antituberculous drugs (ATDs) with antifungals against Coccidioides posadasii. Eighteen drug combinations, formed by an ATD (isoniazid, pyrazinamide or ethambutol) plus an antifungal (amphotericin B, ketoconazole, itraconazole, fluconazole, voriconazole or caspofungin), were tested using the checkerboard method. All the antimicrobial combinations inhibited C. posadasii strains and synergistic interactions were observed for 10 combinations. Antagonism between the tested drugs was not observed. Stronger synergistic interactions were seen in the combinations formed by triazoles plus ethambutol as well as itraconazole plus pyrazinamide. Further studies in animal models are needed to confirm the usefulness of these combinations.