Consumers are denied the freedom to choose from a wide range of goods and services if all firms produce similar products.

Unemployment could result especially as inefficient firms are pushed out of the market.

Research is limited since firms earn only normal profits in the longrun hence no initiative for technology development.

The assumptions of perfect competition are not practical in the real world.

Firms aim at profit maximization as their goal and hence social amenities and public utilities may suffer eg sanitation , water etc.

Expansion of the firms is hampered since there are no huge profits in the longrun to "plough back"

Prices are constant and demand perfectly elastic. This limits the possibility of price discrimination which is sometimes good.