Uranium (U) contamination is a major environmental problem associated with the mining and processing of nuclear materials for both weapons and power production. When possible in situ soil remediation techniques are preferable for reducing the risk associated with diffuse low-level U contamination. Uranium is known to form sparingly soluble phosphate compounds that persist in the environment. Therefore, batch experiments were performed to evaluate the efficacy of three phosphate amendments, hydroxyapatite (HA), sodium phytate (IP6) and sodium tripolyphosphate (TPP), to immobilize U in contaminated sediments. The amendments were added at equivalent phosphorus (P) concentrations and then equilibrated under a range of test conditions, with changes in soluble U and P-total monitored at pre-set time intervals. Only HA was effective at reducing soluble U when compared to the control, with IP6 and TPP increasing soluble U. After equilibration, changes in contaminant partitioning in the amended sediments was evaluated using operational extraction methods.