A pattern matching engine supports high speed (up to at least 2.4. Gbits per second line rate speeds) parallel pattern matching operations in an unanchored fashion. The engine is preferably implemented as a hardware device. A shift register serially receives a string of data stream bytes which are partitioned into a plurality of multi-byte overlapping adjacent stream chunks. Library patterns of bytes to be searched for are similarly partitioned into multi-byte overlapping adjacent table chunks for storage in a look-up table. The plurality of multi-byte overlapping adjacent stream chunks are applied by the register in parallel to the look-up table, with a result being returned which is indicative of whether each stream chunk matches one of the look-up table stored table chunks. The results of the parallel look-up operation are then logically combined to make a match determination.