Instructions and logic provide SIMD secure hashing round slice functionality. Some embodiments include a processor comprising: a decode stage to decode an instruction for a SIMD secure hashing algorithm round slice, the instruction specifying a source data operand set, a message-plus-constant operand set, a round-slice portion of the secure hashing algorithm round, and a rotator set portion of rotate settings. Processor execution units, are responsive to the decoded instruction, to perform a secure hashing round-slice set of round iterations upon the source data operand set, applying the message-plus-constant operand set and the rotator set, and store a result of the instruction in a SIMD destination register. One embodiment of the instruction specifies a hash round type as one of four MD5 round types. Other embodiments may specify a hash round type by an immediate operand as one of three SHA-1 round types or as a SHA-2 round type.