Background: The liver is the most common site for colorectal cancer (CRC) metastases. Their removal is a critical and challenging aspect of CRC treatment. We investigated the prognosis and risk factors of patients with CRC and liver metastases (CRCLM) who underwent simultaneous resections for both lesions. Methods: From January 2009 to August 2016, 102 patients with CRCLM received simultaneous resections of CRCLM at our hospital. We retrospectively analyzed their clinical data and analyzed their outcomes. Overall survival (OS) and disease?free survival (DFS) were examined by Kaplan?Meier and log?rank methods. Results: Median follow?up time was 22.7 months; no perioperative death or serious complications were observed. Median OS was 55.5 months; postoperative OS rates were 1?year: 93.8%, 3?year: 60.7%, and 5?year: 46.4%. Median DFS was 9.0 months; postoperative DFS rates were 1?year: 43.1%, 3?year: 23.0%, and 5?year 21.1%. Independent risk factors found in multivariate analysis included carcinoembryonic antigen ≥100 ng/ml, no adjuvant chemotherapy, tumor thrombus in liver metastases, and bilobar liver metastases for OS; age ≥60 years, no adjuvant chemotherapy, multiple metastases, and largest diameter ≥3 cm for DFS. Conclusions: Simultaneous surgical resection is a safe and effective treatment for patients with synchronous CRCLM. The main prognostic factors are pathological characteristics of liver metastases and whether standard adjuvant chemotherapy is performed.