A man who has been ordained and set apart as the presiding high priest for a ward, or congregation. He has overall responsibility for ministering the temporal and spiritual affairs of the congregation.

During the Worldwide Leadership Training Broadcast, President Thomas S. Monson outlined five responsibilities of a bishop.

His message was based on a presentation regarding the duties of a bishop made by then-Elder Harold B. Lee as he attended stake conference in the Temple View Stake where, at the time, President Monson was serving as a bishop. Thirteen years later, when President Monson was a member of the Quorum of the Twelve, he retrieved his notes of Elder Lee's remarks, and in due time a presentation based on those notes was carried to every stake of the Church.

[1]In the leadership training broadcast President Monson, first counselor in the First Presidency, drew from that presentation as he elaborated on the responsibilities of a bishop:

First, the bishop is the presiding high priest and father of the ward. "As such, (the bishop) presides at sacrament meeting, priesthood meeting, ward council meetings, and at all other ward services and activities," said President Monson. "By these and other means, he watches over both the spiritual and temporal affairs of the ward. He is also responsible for the doctrine which is taught in the ward."

President Monson said a bishop must know his people, their names, circumstances, challenges, goals and abilities. "A wise bishop knows the names of the children in the ward as well, and he remembers them on their birthdays. He also is mindful of the widow and those who, for whatever reason, are not found as regular attenders in the meetings."

Second, the bishop has responsibility for the Aaronic Priesthood. The bishop's duty "is to see that every boy is ordained a deacon at the right age, as well as a teacher, a priest and an elder," President Monson said. He added, "The two words, labor and love, will work wonders in achieving this objective. For those who are behind schedule, I leave the challenge, 'Reach out to rescue.'

"Appoint as advisers to the Aaronic Priesthood quorums brethren who can relate to these young men — who can give them encouragement in the performance of their responsibilities and prepare them to serve at the sacrament table, as home teachers, in the case of teachers and priests, and to qualify for missions."

Next of the bishop's responsibilities is that of caring for the needy. President Monson quoted President J. Reuben Clark Jr., a long-time member of the First Presidency, who said: "To the bishop is given all the powers, and responsibilities which the Lord has specifically prescribed in the Doctrine and Covenants for the caring of the poor. . . . No one else is charged with this duty and responsibility, no one else is endowed with the power and functions necessary for this work. . . . It is (the bishop's) duty and his only to determine to whom, when, how, and how much shall be given to any member of his ward from Church funds and as ward help."

Next, the bishop is responsible for finances. The bishop, President Monson said, receives tithes and offerings, supervises the unit budget and expenditures and makes certain that records are properly and appropriately kept. "The bishop is the one who must determine how Church commodities and funds are used to provide for the temporal needs of the members."

Closely allied to responsibility for finances, he said, is keeping accurate attendance and related records. "Where performance is measured, performance improves. Where performance is measured and reported back, the rate of improvement accelerates," he added.

Finally, the bishop is the common judge. President Monson cited Doctrine and Covenants 107:68, 72 and 74 relative to a bishop's duty "to do the business of the church, to sit in judgment upon transgressors upon testimony as it shall be laid before him according to the laws."

"President Spencer W. Kimball," he said, "provided this wise counsel: When disciplining members of the Church for a transgression, make a bandage large enough to cover the wound — no larger and no smaller."

President Monson cited the instruction of President Gordon B. Hinckley to bishops at the priesthood session of last October's general conference pertaining to this duty. He also recalled the advice given to him as a new bishop by Paul C. Child, a former bishop and stake president: "First, take care of the poor. Second, have no favorites. Third, tolerate no iniquity."

President Monson closed by saying that the "sacred and God-given responsibilities of the bishops were authored in heaven to bless in our day each member of the Church."

References
[1] http://www.ldschurchnews.com/articles/45754/Bishops-duties-outlined-at-training-meeting.html