Abstract: The long-lived uranium isotope ²³⁶U (T_1/2=2.34×10⁷a) is mainly produced by ²³⁵U neutron capture. Accelerator mass spectrometry (AMS) is presently the most sensitive technique for the measurement of ²³⁶U. The sensitivity of ²³⁶U AMS measurement was reported at the Center for Isotopic Research on Cultural and Environmental heritage (CIRCE) at the Second University of Naples, Italy. Also the possible sources of background for ²³⁶U AMS measurement were analyzed. The preliminary results indicate that the sensitivity of ²³⁶U at CIRCE is N(²³⁶U)/N(²³⁸U)= (2.29±0.13)×10^-10.