Sending M.Sc. dissertation to a big conference I am a very recent Ph.D. student (since October 2014), and the deadline date of the conference in which I want to participate is quite near.  I don't want to miss the conference, but as I am so new in my Ph.D. program, I don't have something really concrete for the moment.  For this conference, however, it is possible to revise the paper until 15 days before the conference.

Accordingly, I am thinking of submitting my M.Sc. dissertation to the conference. As I think I will have an improved version of my M.Sc. in 3-4 months (at least, I really hope), I suppose that it is worth doing this.

Is it really a bad idea to submit a M.Sc. dissertation to a conference? Are there some ethical issues to consider?
Typically a dissertation is not considered to be a peer reviewed publication.  This means that the material in it can be extracted and turned into conference or journal publications.  In some fields, this is a typical practice after completing a dissertation, where in others it goes the other way (the dissertation is assembled from peer-reviewed papers).

You cannot, however, just submit your thesis directly as is.  A dissertation is generally much longer than conference or journal papers.  A dissertation typically also has much more freedom in style, and does not have to be targeted at the biases of a particular community.  Thus, to make a credible conference submission, you will need to compress or extract a nugget of contribution of an appropriate size, and may also need to tailor its focus and language to better match that of the conference where it is being submitted.