There were 14,603 murders from January to June, versus the 13,985 homicides registered in the first six months of 2018, according to data posted over the weekend on the website of Mexico's national public security office.
Mexico is on course to surpass the 29,111 murders of last year, an all-time high.
For years Mexico has struggled with violence as consecutive governments battled brutal drug cartels, often by taking out their leaders. That has resulted in the fragmentation of gangs and increasingly vicious internecine fighting.
Veteran leftist Lopez Obrador, who took office in December, has blamed the economic policies of previous administrations for exacerbating the violence and said his government was targeting the issue by rooting out corruption and inequality in Mexico.
"Social policies are very important - we agree they'll have positive effects. But these positive effects will be seen in the long term," said Francisco Rivas, director of the National Citizen Observatory, a civil group that monitors justice and security in Mexico.
The complexity of fighting criminal groups is a major test for Lopez Obrador's young administration, which has vowed to try a different approach than that of his predecessor.
His administration last month launched a new militarised National Guard police force tasked with helping to fix the problem.
