Jim Murphy was responding to former Tory chairman Lord Baker's view that there could be a deal between the two rival parties after May's election.
However, the Labour MP has not ruled out some kind of deal with the SNP.
Mr Murphy told BBC political editor Brian Taylor that it was "disrespectful" to discuss political deals before the general election.
On the suggestion of his party entering into a Conservative arrangement in the event of a hung parliament, Mr Murphy was very clear.
He said: "We don't need lessons from Tory dinosaurs about how to run Scotland, what a ludicrous idea."
Mr Murphy added that the differences between the Labour Party and the Conservative Party were bigger than "I have seen for a number of years".
Writing in The Independent, Lord Baker of Dorking said a Labour minority government reliant on the SNP would be a "nightmare" situation at Westminster.
He added that such an arrangement could "stretch the constitution of our country to breaking point".
However, the SNP said it was trusted more than Labour to keep the Tories out.
Asked if a deal with the nationalists was possible, Mr Murphy said he did not want to get into a "post-match analysis on an event that has not yet taken place".
He told Brian Taylor during a half-hour webcast: "As I say, if the SNP want to vote for our policies in the House of Commons, it's up to them - some time they have done that in recent times, quite often they have sided with the Tories against Labour."
Mr Murphy said he had no desire to focus on the "politics of pessimism" because he wanted his party to win government.
The debate over coalition deals has arisen because polling suggests neither Labour nor the Conservatives would gain an overall majority in this year's election.
If that is the case a coalition deal with smaller parties could be possible or a so-called "confidence and supply" arrangement could be agreed whereby the smaller party supports the larger party in key votes.
During the webchat Mr Murphy was also asked about tuition fees, the Scottish independence referendum and his decision to fight his East Renfrewshire seat in May.

Ashbourne's Royal Shrovetide Football game involves two sides competing to move a ball to posts at opposing ends of the town.
It takes place across fields, streets, car parks and waterways each Shrove Tuesday and Ash Wednesday.
The game was won 1-0 by the Up'Ards, who defeated the Down'Ards in the two-day event.
The Up'Ards - traditionally those born north of Henmore River - play against the Down'Ards from the south of the town's river.
Each game begins with a guest of honour throwing the elaborately painted ball into the crowd.
Prince Charles and the late Nottingham Forest and Derby County football manager Brian Clough are among the famous names chosen to "turn up" the ball in previous years.
This year the honour fell to Dallas Burston, a former GP who became a businessman, and John Stubbs, a retired dairy farmer.
Shop windows around the town were again boarded up ahead of the famously hard-fought contest.
Players were also reminded they were not allowed to climb over parked cars or enter cemeteries, churchyards and memorial gardens.
A goal was scored by Kurt Smith at about 20:20 GMT on Tuesday and it took nearly and hour for it to be confirmed. There were no goals on Wednesday.

Shaun Ritchie, from Fraserburgh, was last seen with friends at a remote woodland area near Strichen at the end of October last year.
The operation is one of Police Scotland's longest-running missing persons inquiries.
The force said there was no evidence of a crime.
Det Ch Insp Matt Mackay said: "We are trying to bring closure to the family.
"It's one of the longest-running inquiries. It's such a vast area. It takes time."
The leader of the Scottish Labour Party has called the idea of a Conservative-Labour coalition "ludicrous".
[NEXT_CONCEPT]
Play has ended in a mass game of football that has been played in a Derbyshire town for centuries.
[NEXT_CONCEPT]
Police say they want to help bring "closure" to the family of a missing Aberdeenshire man, one year after his disappearance.