The relationship of the Southern Oscillation and El Niño phenomena to sea surface temperature anomalies in the Indonesian region is investigated. The three are closely related and the relationship has a strong annual cycle. The Indonesian sea surface temperature anomalies show arena persistence approximately from January through October with a tendency to dissipate or change sign around November. Changes of Indonesian sea surface temperature anomalies lead by about a season changes in the Southern Oscillation and east Pacific sea surface temperature. It is demonstrated that a simple ad hoc model representing a stochastically-forced, seasonally-varying interaction between the atmosphere and the ocean in the Indonesian region can product simulated anomalies at Darwin pressure and Indonesian sea surface temperature that reproduce the observed statistical behavior of them anomalies without the inclusion of the effects of oceanic and atmospheric events external to the Indonesian region. It suggested that the El Niño-Southern Oscillation might be the dynamic response of the Pacific Ocean and overlying atmosphere to anomalies produced by such an interaction in the Indonesian region. A speculation is raised involving the possible physical basis for such an interaction.