Primary liver cancer is the sixth most frequent tumor worldwide, with rising incidence and wide geographic range. The management of hepatocellular carcinoma (HCC) and cholangiocarcinoma (CCC) is complex and expensive when detected before disseminated disease occurs. Metastatic cancer to the liver is more common than primary tumors. Metastatic colorectal (mCRC) and neuroendocrine tumors (mNET) are the malignancies most frequently responsive to locoregional therapy. 143 patients were treated with laparoscopic, ultrasound-guided microwave ablation (LMA) for the management of primary and metastatic malignancy to the liver alone or in combination with additional loco-regional therapy (Y-90 radioembolization) and/or systemic chemotherapy or immunotherapy Patients selected for LMA underwent a staging laparoscopy and lysis of adhesions when indicated. Those with extrahepatic disease identified by laparoscopy that was not detected by preoperative imaging studies were excluded. A laparoscopic ultrasound probe was used to identify the tumor burden sites. With ultrasound guidance an automated 16 gauge needle was used to obtain tumor tissue. Once the diagnosis of malignancy was confirmed histologically by frozen section, a 2.4 gHz microwave antenna was introduced with ultrasound guidance for ablation. The energy used, time of ablation and number of antenna placements varied depending on the size of the tumor, shape and locations within the liver. 143 patients underwent 211 LMAs in a 6 year period. Mean age: 68 (23 - 86). Males:female 59:41%. HCC 52% (n=68), CCC 3% (n=4). mCRC 24% (n=32), mNET 7.5% (n=10), others tumors 14% (n=20). 83% (n=119) underwent one LMA, 17% (n=24), had two or more LMAs. By imaging studies and tumor markers 83% had R0 ablations and 17% had recurrent disease. Average time for a second primary or recurrent disease to occur: 23 months. Operative mortality 0.7% (n=1), complication rate: 11%, primarily from bowel injury secondary to extensive lysis of adhesions. Conclusions: LMA is a safe treatment option with minimal mortality, and few complications. There is a high rate of R0 ablation, prolongation of disease free survival, and plays a significant role in the multimodality treatment for primary and secondary liver malignancies.