Joint Filing Agreement

Exhibit 6

Joint Filing Agreement

The undersigned hereby agree that a single Schedule 13D (or any amendment thereto) relating to the Common Stock of Helicos Biosciences Corporation shall be filed on behalf of each of the undersigned and that this Agreement shall be filed as an exhibit to such Schedule 13D.

Date: September      , 2009

Versant Ventures II, LLC
By:		/s/ Xxxxx X. Xxxxxx						/s/ *
		Name:		Xxxxx X. Xxxxxx				Xxxxx X. Xxxxxx
				Managing Director
								/s/ *
								Xxxxxxx X. Xxxxxx
Versant Venture Capital II, L.P.								/s/ *
By its General Partner, Versant Ventures II, LLC								Xxxxxx X. Xxxxxxx
By:		/s/ Xxxxx X. Xxxxxx						/s/ *
		Name:		Xxxxx X. Xxxxxx				Xxxx X. Xxxxx
				Managing Director
								/s/ *
								Xxxxxxx X. Link
Versant Side Fund II, L.P.								/s/ *
By its General Partner, Versant Ventures II, LLC								Xxxxxxx X. Xxxxxx
By:		/s/ Xxxxx X. Xxxxxx						/s/ *
		Name:		Xxxxx X. Xxxxxx				Xxxxxx X. Xxxxxx
				Managing Director
								/s/ *
								Xxxxxxx X. Xxxxxxxxx
Versant Affiliates Fund II-A, L.P								/s/ *
By its General Partner, Versant Ventures II, LLC								Xxxxxxx X. Xxxxxxx
By:		/s/ Xxxxx X. Xxxxxx						/s/ *
		Name:		Xxxxx X. Xxxxxx				Xxxxxxx X. Xxxxxx
				Managing Director

	*By:	/s/ Xxxxx X. Xxxxxxx
		Xxxxx X. Xxxxxxx, Attorney-in-Fact