There were actually 2 versions of the theme song for the show Bonanza. The second, and most widely known because it actually aired with the show, was written by Jay Livingston and Ray Evans. This theme was sung by Lorne Greene. Here are the lyrics (as if you couldn’t recite them from memory):

We chased lady luck, 'til we finally struck Bonanza.
With a gun and a rope and a hat full of hope, planted a family tree.
We got hold of a pot of gold, Bonanza.
With a horse and a saddle, and a range full of cattle, how rich can a fellow be?

On this land we put our brand, Cartwright is the name,
fortune smiled, the day we filed the Ponderosa claim.
Here in the West, we're livin' the best, Bonanza,
if anyone fights any one of us, he's go a fight with me, Bonanza.

Hoss and Joe and Adam know every rock and pine,
no one works, fights, or eats, like those boys of mine.
Here we stand in the middle of a grand Bonanza.
With a gun and a rope and a hatful of hope, we planted our family tree,
we got hold of a potful of gold, Bonanza.

With a houseful of friends where the rainbow ends, how rich can a fellow be?
On this land we put our brand, Cartwright is the name,
fortune smiled, the day we filed the Ponderosa claim.
Here in the west we're livin' the best Bonanza.

With the friendliest, fightingist, loving band, that ever set foot in the promised land,
and we're happier than them all.
That's why we call it Bonanza...Bonanza...Bonanza...



The first version of the theme song, which was recorded and intended to air with the pilot episode "A Rose for Lotta", was sung by Hoss (Dan Blocker), Little Joe (Michael Landon) and Ben (Lorne Greene). The producers of the show rejected the theme and decided to go with the above version before the first episode aired. Here’s the original theme’s lyrics:

Little Joe (solo):
I've got a flair for women everywhere---Bonanza!

Hoss (solo):
Bonanza! (Barks and howls)

Hoss, Joe and Ben:
I'm not afraid of any pretty maid--Bonanza! Bonanza!
But when I give a kiss to any little miss,
She'll learn a lot from me.

Ben (solo):
I'm not afraid of any pretty maid--Bonanza!

Hoss, Joe and Ben:
Bonanza!
When I give a kiss to any little miss
She'll learn a lot from me
Hair of brown, hair of gold
I'll take what I see

We're not a one to saddle up and run--Bonanza! Bonanza!
Anyone of us who starts a little fuss
Knows he can count on me
One for four, four for all
This we guarantee

We got a right to pick a little fight--Bonanza! Bonanza!
If anyone fights any one of us
He's gotta fight with me!



This node brought to you by the Everyone Should Memorize the Lyrics to Bonanza League.

Sources:
ponderosascenery.homestead.com/lyrics.html
www.findagrave.com/php/famous.php?page=pr&FSctf=110