Kosmos 138 (Russian: Космос 138 meaning Cosmos 138) or Zenit-2 No.43 was a Soviet, first generation, low resolution, optical film-return reconnaissance satellite launched in 1967.

A Zenit-2 spacecraft, Kosmos 138 was the forty-fifth of eighty-one such satellites to be launched[3][4] and had a mass of 4,730 kilograms (10,430 lb).

Kosmos 138 was launched by a Vostok-2 rocket, serial number N15001-05,[5] flying from Site 41/1 at the Plesetsk Cosmodrome.

[1] The satellite reached a slightly lower orbit than had been planned, but was still able to complete its mission.

[2] After 8 days in orbit, Kosmos 138 was deorbited, with its return capsule descending under parachute, landing at 06:14 GMT on 27 January 1967, and recovered by Soviet force.