Molybdenum was not discovered until the latter part of the 18th century, and does not occur in the metallic form in nature. Despite this, its predominant mineral - molybdenite - was used in ancient times (a 14th-century Japanese sword has been found to contain molybdenum) but would have been indistinguishable from other similar materials such as lead, galena and graphite. Collectively, these substances were known by the Greek word “molybdos”, which means lead-like.

Molybdenum was first positively identified in 1778 by a Swedish scientist, Carl Wilhelm Scheele. Shortly thereafter, in 1782, Peter Jacob Hjelm reduced molybdenite oxide with carbon to obtain a dark metallic powder which he named “molybdenum”.

Molybdenum remained a laboratory curiosity throughout most of the 19th century until the technology for the extraction of commercial quantities became practical. In 1891, the French company Schneider and Co. first used molybdenum as an alloying element in the production of armor plates. It was quickly noted that molybdenum was an effective replacement for tungsten in numerous steel alloying applications because its density is only slightly more than half that of tungsten.