An LED lamp includes a lamp holder, a heat sink, a plurality of LED modules, a cover, an envelope and a sealing cushion. The lamp holder has a connecting portion at a bottom thereof adapted for engaging with a lamp socket to fix the LED lamp in position. The heat sink is disposed on the lamp holder. The LED modules are attached to a circumference of the heat sink. The cover is coupled to a top of the heat sink. The envelope encloses the heat sink and the LED modules therein and has a lower end engaging with the lamp holder and an upper end engaging with the cover. The sealing cushion is provided between at least one of the combinations of the lamp holder and the envelope, and of the cover and the envelope to prevent an entry of foreign matter.