Background: Intravascular ultrasound (IVUS) analysis software enables precise planimetry measurement and tissue characterization of coronary plaque. Recently, a new IVUS analysis software compatible with integrated backscatter-IVUS, VISIATLAS^TM, was developed. The validity and reliability of VISIATLAS^TM were evaluated. Methods and Results: Forty patients who underwent IVUS-guided percutaneous coronary intervention were enrolled, and planimetry measurements were performed by 2 observers using VISIATLAS^TM and echoPlaque^TM. IVUS analysis was performed in non-stent segments in 10 patients (non-target vessel, n=5; target vessel before stent implantation, n=5) at every 2.5mm for 20 slices in each patient. Stent segments were analyzed in the remaining 30 patients. With VISIATLAS^TM, the intraobserver and interobserver intraclass correlation coefficients (ICC) for the area of external elastic membrane (EEM), lumen, and plaque plus media (P+M) were 0.999 and 0.999, 0.996 and 0.993, and 0.993 and 0.991, respectively. The intersoftware ICC for EEM, lumen, and P+M area were 0.997, 0.993, and 0.985, respectively. The ICC of stent volume for intraobserver, interobserver and intersoftware comparisons were 0.997, 0.993, and 0.998, respectively. Bland-Altman plots showed small differences and narrow limits of agreement for all of the above parameters. Conclusions: VISIATLAS^TM has high repeatability and reproducibility of measurement. This new IVUS analysis software is suitable for accurate measurement of coronary artery and stent structure in future IVUS studies.  (Circ J 2013; 77: 424–431)