Wellington's army, which numbered up to 40,000 men, faced a small French garrison of 1,800 troops under the command of Jean Léonard Barrié.

[3] Ciudad Rodrigo was a second class fortress with a 32-foot (9.8 m) high main wall built of "bad masonry, without flanks, and with weak parapets and narrow ramparts."

The French garrison included single battalions of the 34th Light and 113th Line Infantry Regiments, a platoon of sappers and only 167 artillerists to man 153 cannons.

The defenders made a vigorous sortie at 11 am on 14 January with 500 men, as the troops were being relieved, this sortie was repulsed, and that night an escalade was mounted against the San Francisco Convent, on the left, by men from the 40th Regiment of Foot which was successful, all French troops falling back inside the city walls.

Diversionary attacks by Denis Pack's Portuguese brigade would probe the defences at the San Pelayo Gate on the east and across the Agueda River on the south.

Allied losses in the assault were 195 killed and 916 wounded, but among the dead were Major-Generals Henry MacKinnon and Robert Craufurd.

[7] The victory was somewhat marred when the British rank and file, who were upset by the 562 casualties suffered during the storming of the town, thoroughly sacked the city, despite the efforts of their officers to rein them in, which they eventually managed to do so.

The rapid loss of Ciudad Rodrigo badly upset the calculations of Marmont who believed that the city would hold for three weeks, which would give him enough time to concentrate a relief force at Salamanca.