Calderon is conducting a series of public conferences on anti-crime strategies, amid increasing criticism of his offensive against drug gangs in which more than 28,000 people have died in drug-related violence since late 2006.
"There are a large number of people who are detained in police actions, caught in the act or in the company of other criminal suspects, and not withstanding that, the number of people who are finally brought to trial or convicted is significantly less," Calderon said at a meeting of officials from Mexico's judicial branch.
Calderon did not offer any specific figures on the conviction rate, but figures obtained by The Associated Press indicate that only about 15 percent of drug suspects detained between December 2006 and September 2009 have been convicted or acquitted.
The chief justice of Mexico's Supreme Court, Guillermo Ortiz, said Wednesday that while some charges are dismissed for lack of evidence, 85 percent of people formally held over for trial on crimes in general are convicted.
But officials also acknowledged that a highly touted legal reform allowing the government to seize alleged drug traffickers' property before they are convicted has been of little use since it was enacted in May 2009.
Ortiz said less than 10 cases had been brought under the property seizure law, saying it had "been of little use."
Attorney General Arturo Chavez said the law has been hampered because it requires prosecutors to reveal evidence from criminal cases to prove they have grounds for the seizures.
Criminal cases are usually kept sealed in Mexico.
Mexico has been under increasing pressure to combat an estimated flow of as much as $10 billion a year in suspicious funds possibly linked to drug trafficking.
Elsewhere on Wednesday, police in the northern state of Chihuahua reported finding four dead men tied to a fence in the crucifix position and five others shot to dead inside a ranch home.
The Chihuahua state prosecutors office said the men were tied to the fence with ropes, and a sign found nearby read: "Keep sending us kidnappers, and we will kill them."
The bodies were found on the side of a highway near the city of Cuauhtemoc.
Police also found the bodies of five people inside a ranch in the town of Villahumada. All had been shot to death, Chihuahua state prosecutors' spokesman Arturo Sandoval said.
In the northern state of Durango, state prosecutors reported Wednesday they had found the hacked-up bodies of three people stuffed into sacks in the city of Santiago Papasquiaro.
The sacks were dumped on a street. The victims had been dead for around a day by the time their bodies were found.