Sangma made the appeal here at the main Independence Day celebration attended by thousands of people despite rains and boycott calls by militants.
"I call upon all the misguided youth (militants) waging war against the nation and our own people to realize the futility of violence," he said in his speech.
He urged them to take advantage of the government's offer to come overground and avail the rehabilitation package.
"Violence has never been an option for providing any solution to grievances," Sangma said. "There is no issue that does not lend itself to solution through meaningful engagement and reconciliation."
He said the decades old militancy can be addressed effectively through a multipronged approach by looking at the root cause.
"These problems have also been posing serious challenges to many of our neighbouring northeastern states, particularly states having porous border with our neighbouring countries.
"Hence, there is a need for a coordinated approach along with the active support of the central government to tackle the problems of militancy effectively."
Thousands of people attended the official celebrations across Meghalaya despite the inclement weather and a shutdown called by the outlawed Hynniewtrep National Liberation Council (HNLC) and the A'chik Songna An'pachakgipa Kotok (ASAK) groups.
The HNLC, which conducts hit-and-run operations from Bangladesh, wants a sovereign Hynniewtrep homeland in Meghalaya's eastern part. The ASAK, which means "vanguards of Garoland", is demanding a separate Garoland out of Meghalaya.
The chief minister praised the security forces for their operations against the militants.
He said the central government had approved the Agreed Text of Settlement with the A'chik National Volunteers Council (ANVC), a Garo rebel outfit.
Sangma said a comprehensive mechanism to deal with the issue of influx and illegal immigration would be put in place at the earliest.