The 2010 floods in Pakistan began in late July, resulting from heavy monsoon rains in the Khyber Pakhtunkhwa, Sindh, Punjab and, Balochistan regions of Pakistan, which affected the Indus River basin. Approximately one-fifth of Pakistan's total land area was affected by the floods, with the Khyber Pakhtunkhwa province facing the brunt of the damage and casualties (above 90% of all the deaths occurred in the province). Nationwide, there were 1,985 deaths. According to Pakistani government data, the floods directly affected about 20 million people, mostly by destruction of property, livelihood and infrastructure.

UN Secretary-General Ban Ki-moon had initially asked for US$460 million (€420 million) for emergency relief, noting that the flood was the worst disaster he had ever seen. Only 20% of the relief funds requested had been received by 15 August 2010. The U.N. had been concerned that aid was not arriving fast enough, and the World Health Organization reported that ten million people were forced to drink unsafe water. The Pakistani economy was harmed by extensive damage to infrastructure and crops. Damage to structures was estimated to exceed US$4 billion (€2.5 billion), and wheat crop damages were estimated to be over US$500 million (€425 million). Total economic impact may have been as much as US$43 billion (€35 billion).

The floods were driven by rain. The rainfall anomaly map published by NASA showed unusually intense monsoon rains attributed to La Niña. On 21 June, the Pakistan Meteorological Department cautioned that urban and flash flooding could occur from July to September in the north parts of the country. The same department recorded above-average rainfall in the months of July and August 2010 and monitored the flood wave progression. Discharge levels were comparable to those of the floods of 1988, 1995, and 1997. The monsoon rainfall of 2010 over the whole country was the highest since 1994 and the second highest during last 50 years.

A research by Utah State University analyzed conditional instability, moisture flux, and circulation features and the results support a persistent increase in conditional instability during the July premonsoon phase, accompanied by increased frequency of heavy rainfall events. The increased convective activity during the premonsoon phase agrees with the projected increase in the intensity of heavy rainfall events over northern Pakistan. Large-scale circulation analysis reveals an upper-level cyclonic anomaly over and to the west of Pakistan–a feature empirically associated with weak monsoon. The analysis also suggests that the anomalous circulation in 2010 is not sporadic but rather is part of a long-term trend that defies the typical linkage of strong monsoons with an anomalous anticyclone in the upper troposphere. An article in the New Scientist attributed the cause of the exceptional rainfall to "freezing" of the jet stream, a phenomenon that reportedly also caused unprecedented heat waves and wildfires in Russia as well as the 2007 United Kingdom floods.

In response to previous Indus River floods in 1973 and 1976, Pakistan created the Federal Flood Commission (FFC) in 1977. The FFC operates under Pakistan's Ministry of Water and Power. It is charged with executing flood control projects and protecting lives and property of Pakistanis from the impact of floods. Since its inception the FFC has received Rs 87.8 billion (about US$900 million). FFC documents show that numerous projects were initiated, funded and completed, but reports indicate that little work has actually been done due to ineffective leadership and corruption.

Monsoon rains were forecast to continue into early August and were described as the worst in this area in the last 80 years. The Pakistan Meteorological Department reported that over 200 millimetres (7.9 in) of rain fell over a 24-hour period in Khyber Pakhtunkhwa and Punjab. A record-breaking 274 millimetres (10.8 in) rain fell in Peshawar during 24 hours; the previous record was 187 millimetres (7.4 in) of rain in April 2009. On 28 July, the same heavy rains contributed to the crash of Airblue Flight 202 in the Margalla Hills. On 30 July 500,000 or more people had been displaced from their homes. On 30 July, Manuel Bessler, head of the UN Office for the Coordination of Humanitarian Affairs, stated that 36 districts were involved, and 950,000 people were affected, although within a day, reports increased that number to as high as a million, and by mid-August they increased the number to nearly 20 million affected.

By mid-August, according to the governmental Federal Flood Commission (FFC), the floods had caused the deaths of at least 1,540 people, while 2,088 people had received injuries, 557,226 houses had been destroyed, and over 6 million people had been displaced. One month later, the tally had risen to 1,781 deaths, 2,966 people with injuries, and more than 1.89 million homes destroyed.

The Khyber Pakhtunkhwa provincial minister of information, Mian Iftikhar Hussain, said "the infrastructure of this province was already destroyed by terrorism. Whatever was left was finished off by these floods." He also called the floods "the worst calamity in our history." Four million Pakistanis were left with food shortages.