An organic electroluminescent device includes: first and second substrates facing each other and spaced apart from each other, the first and second substrates having a central portion and a peripheral portion; an array layer on the first substrate, the array layer including a thin film transistor; an organic electroluminescent diode on the second substrate; a connection pattern between the first and second substrates, the connection pattern electrically connecting the thin film transistor and the organic electroluminescent diode; and a seal pattern in the peripheral portion, the seal pattern including a metallic material for attaching the first and second substrates.