Long queues were seen since early morning at many polling stations in 13 districts.
Technical snag in Electronic Voting Machines (EVMs) delayed start of the polling at few places. Chief Electoral Officer Bhanwarlal said the faulty EVMs were replaced within few minutes.
About 10 percent votes were polled in the first two hours at 40,709 polling stations.
Tension prevailed at some polling stations in Kadapa, Anantapur, Chittoor and Guntur districts due to clashes between activists of the YSR Congress Party (YSRCP) and the Telugu Desam Party (TDP).
About 36.76 million people are eligible to vote in the second phase which will cover nine districts in coastal Andhra and four in Rayalaseema.
Seemandhra, as the two regions are together called, will come into being as separate state of Andhra Pradesh June 2 with the formation of Telangana region as a separate state.
As many as 335 candidates are in the fray for the Lok Sabha elections while 2,241 contestants are testing their political fortunes in the assembly polls.
Polling, which began at 7 a.m., will conclude at 4 p.m. in two Maoist affected assembly constituencies and at 5 p.m. in eight segments. In the remaining 165 constituencies, the polling will end at 6 p.m.
Over 100,000 police personnel and 272 companies of central paramilitary forces have been deployed as part of the massive security arrangements.
The poll officials are keeping a tight vigil in certain pockets of Rayalaseema and coastal Andhra notorious for electoral malpractices.
The most prominent among the contestants for Lok Sabha elections are cabinet ministers and Congress leaders Kishore Chandra Deo (Araku) and Pallam Raju (Kakinada), YSR Congress honorary president Y.S. Vijayamma (Visakhapatnam) and former central minister D. Purandeswari of BJP (Rajampet).
In the assembly polls for Seemandhra region, chief ministerial hopeful and Telugu Desam Party state president N. Chandrababu Naidu is contesting from Kuppam assembly constituency.
Another chief ministerial aspirant and YSR Congress president Y.S. Jagan Mohan Reddy is fighting his first ever assembly election from the family stronghold Pulivendula.(ians)