In the in situ degradation of formaldehyde with electrogenerated hydrogen peroxide, the cathodic reduction of oxygen on the anodization graphite was first order in the concentration of oxygen dissolved in the aqueous phase. The oxidation of formaldehyde with electrogenerated hydrogen peroxide was second order in formaldehyde and first order in hydrogen peroxide. The activation energy was evaluated as 36 kJ mol-1. A model calculation of the in situ degradation of formaldehyde with electrogenerated hydrogen peroxide correlated well with experimental results. The effects of temperature and initial concentration of formaldehyde on the induction period of the oxidative degradation of formaldehyde with hydrogen peroxide electrogenerated in situ were explored.