Roman denarii, small silver coins.

Ancient Rome commanded a vast area of land, with tremendous natural and human resources. As such, Rome's economy remained focused on agriculture and trade. Agricultural free trade changed the Italian landscape, and by the 1st century BC, vast grape and olive estates had supplanted the yeoman farmers, who were unable to match the imported grain price. The annexation of Egypt, Sicily and Tunisia in North Africa provided a continuous supply of grains. In turn, olive oil and wine were Italy's main exports. Two-tier crop rotation was practiced, but farm productivity was overall low, around 1 ton per hectare.

Industrial and manufacturing activities were smaller. The largest such activity were the mining and quarrying of stones, which provided basic construction materials for the buildings of that period. In manufacturing, production was on a relatively small scale, and generally consisted of workshops and small factories that employed at most dozens of workers. However, some brick factories employed hundreds of workers.

Some economic historians (like Peter Temin) argue that the economy of the Early Roman Empire was a market economy and one of the most advanced agricultural economies to have existed (in terms of productivity, urbanization and development of capital markets), comparable to the most advanced economies of the world before the Industrial Revolution, namely the economies of 18th century England and 17th century Netherlands. There were markets for every type of good, for land, for cargo ships; there was even an insurance market.

The economy of the early Republic was largely based on smallholding and paid labor. However, foreign wars and conquests made slaves increasingly cheap and plentiful, and by the late Republic, the economy was largely dependent on slave labor for both skilled and unskilled work. Slaves are estimated to have constituted around 20% of the Roman Empire's population at this time and 40% in the city of Rome. Only in the Roman Empire, when the conquests stopped and the prices of slaves increased, did hired labor become more economical than slave ownership.

Although barter was used in ancient Rome, and often used in tax collection, Rome had a very developed coinage system, with brass, bronze, and precious metal coins in circulation throughout the Empire and beyond—some have even been discovered in India. Before the 3rd century BC, copper was traded by weight, measured in unmarked lumps, across central Italy. The original copper coins (as) had a face value of one Roman pound of copper, but weighed less. Thus, Roman money's utility as a unit of exchange consistently exceeded its intrinsic value as metal. After Nero began debasing the silver denarius, its legal value was an estimated one-third greater than its intrinsic.

Horses were too expensive, and other pack animals too slow, for mass trade on the Roman roads, which connected military posts rather than markets, and were rarely designed for wheels. As a result, there was little transport of commodities between Roman regions until the rise of Roman maritime trade in the 2nd century BC. During that period, a trading vessel took less than a month to complete a trip from Gades to Alexandria via Ostia, spanning the entire length of the Mediterranean. Transport by sea was around 60 times cheaper than by land, so the volume for such trips was much larger.