Voting in six parliamentary constituencies ended at 4pm Thursday, with low turnouts and some disturbances reported in Bogra.
Election commissioner M Sohul Hussain estimated around 50 percent of voters turned out to cast their ballots in the by-elections.
With 1,842,000 registered voters, 17 candidates were contesting in the polls to Bogra- 6 and 7, Rangpur- 3 and 6, Kurigram -2 and Kishoreganj-6 seats.
"Polling was peaceful in most areas," said Sohul.
Some disturbances
Seven people, two BNP and five Awami League activists, were injured in several polling centres in the by-elections to Bogra-6 and 7 constituencies.
The supporters of the two parties clashed in five centres.
One Awami League activist was arrested on charges of violence and polling officer Shawkat Ali detained on charges of campaigning for the BNP candidate in separate incidents.
CEC predicted low turnout
Chief election commissioner ATM Shamsul Huda predicted a low turnout, on the eve of the by-polls, compared to the Dec 29 general election.
"Voters may be a bit reluctant to go to polling stations, as this is the third occasion after parliamentary and Upazila elections, within a relatively short period," he said on Wednesday.
"Besides, farmers are busy with irrigation."
The CEC said the commission had taken all steps for free and fair election.
"I don't see any sign of possible rigging in the elections, there is no such scope," said Huda.
The EC appointed its own officials as returning officers for the first time in parliamentary polls.
In another rarity, the army and BDR were not being deployed to maintain election security, in the wake February's mutiny.
Election officials said greater numbers of RAB, police and ansars were engaged instead.
Election campaigning came to a stop on Tuesday midnight, bans were imposed on all vehicular movement from Wednesday midnight and a public holiday was declared in election areas for convenience of voters.
7 seats vacated, Bagerhat-1 already filled
Six constituencies, two each, were vacated by prime minister Sheikh Hasina, Jatiya Party chairman HM Ershad and BNP chairperson Khaleda Zia when they took up their seats in parliament in january.
A seventh was vacated when Md Zillur Rahman was elected president.
Zillur vacated Kishoreganj-6, Hasina Rangpur-6 and Bagerhat-1, Ershad Rangpur-3 and Kurigram-2, and Khaleda Bogra-6 and 7.
Hasina's cousin Sheikh Helal Uddin was declared elected uncontested to Bagerhat-1 on Mar 17.