Patients with metastatic colorectal carcinoma (CRC) often develop bone metastases with a high risk of complications. Ibandronate is a novel single-nitrogen bisphosphonate that has been shown to be effective for treating bone metastases from breast cancer. A randomized, placebo-controlled trial was conducted to evaluate the efficacy and safety of ibandronate in patients with bone metastases from CRC. The primary efficacy end point was the proportion of patients with skeletal-related events (defined as pathologic fracture, spinal cord compression, radiation therapy to bone, change in antineoplastic therapy or surgery to bone). Secondary end points included time to first skeletal event, skeletal morbidity rate (events/year) and time to progression of bone lesions. In 73 patients with CRC, treatment with intravenous ibandronate 6 mg administered via a 15-min infusion significantly reduced the proportion of patients with skeletal events (39% vs. 78% with placebo; P = 0.019) and prolonged the time to first event by at least 6 months (median >279 vs. 93 days with placebo; P = 0.009). Ibandronate also significantly reduced the skeletal morbidity rate (mean 2.36 vs. 3.14 with placebo; P = 0.018) and prolonged time to progression of bone lesions (214 days vs. 81 days with placebo; P = 0.018). Ibandronate was well tolerated with very rare grade 3 or 4 toxicity. Furthermore, the incidence of renal adverse events was comparable with placebo and there were no clinically relevant changes in serum creatinine. Ibandronate provided significant clinical benefits for patients with bone metastases secondary to CRC. These results indicate that ibandronate may be an effective treatment for patients with metastatic bone disease following CRC. Larger studies are required for further assessment.