The dielectric properties from a set of molybdenum-containing (Mo) diamond-like carbon (DLC) films deposited using electron cyclotron resonance chemical vapor deposition (ECR-CVD) were investigated. It is shown that the film permittivity can be greatly increased by the introduction of Mo, and a sharp decrease in permittivity occurs at low frequencies. The AC conductivity exhibits three characteristic regions in the frequency range investigated. The high epsilon" and tandelta at low frequencies resulted from the high DC conductivity of the films. The peaks at approximately 0.8 kHz in epsilon" and at approximately 4 kHz in tandelta for the film with Mo content of 3% are attributed to the relaxation polarization which has a lagging effect in response to an AC field. It is found that the film permittivity decreases following the decrease in temperature, followed by saturation, and for the film with high Mo content, it is frequency dependent at low temperature. However, for the high frequency of 1 MHz, the film permittivity is weakly Mo dependent at temperatures below 145 K. The relaxation time decreases with increasing Mo content in the films at room temperature. Several possible polarization mechanisms were proposed for our films based on the measurements. The effect of voltage on the film permittivity was also investigated and was found to be insignificant at frequencies above 10 kHz.