Background Paranasal augmentation was effective management for midface concavity. Both alloplastic graft (e.g. silicone, porous polyethylene, or expanded polytetrafluorethylene) and autologous tissue (e.g. costal cartilage) were used for paranasal augmentation. The study aims to evaluate the safety and efficacy of paranasal augmentation using diced costal cartilage for midface concavity. Methods A retrospective review of demographic data and complications was conducted for consecutive patients who underwent paranasal augmentation using diced costal cartilage. A questionnaire was used for investigating the patient's satisfaction (i.e. overall satisfaction, bilateral alar bases symmetry, improvement of concavity, and foreign body sensation). Patients' photographs were used to evaluate aesthetic outcomes (i.e. overall satisfaction, bilateral alar bases symmetry, and improvement of concavity) by third-party doctors. Results Sixty-eight patients (60 females; mean age, 27.1 ± 8.2 years) were included. During a median follow-up of 6.5 months, costal cartilage migration occurred in 13 (19.1%) patients and partial resorption occurred in 2 (2.9%) patients. Seventy-five per cent of the patients and 98.5% of the doctors reported overall satisfaction. Bilateral alar bases asymmetry by 20 (29.4%) patients, no improvement of concavity by 13 (19.1%) patients, and foreign body sensation by 13 (19.1%) patients were reported. While bilateral alar bases asymmetry was not reported, improvement of concavity was reported in 67 (98.5%) patients by third-party doctors. On both univariate and multivariate analyses, improvement of concavity was significantly associated with patients' overall satisfaction (p = 0.008 and 0.045, respectively), while bilateral alar bases symmetry and foreign body sensation were not (all p [ 0.05). Conclusions Paranasal augmentation using diced costal cartilage seems a safe and effective method for midface concavity. Improvement of concavity may be significantly associated with patients' overall satisfaction.