The  third  edition  of  SWAT4LS  was  held  in  Berlin  on  December  10th,  2010.  The   workshop  was  attended  by  about  70  people,  with  a  worldwide  attendance.   Keynotes  were  given  by  Prof.  Jonas  Almeida:  Development  of  Integrative   Bioinformatics  Applications  using  Cloud  Computing  resources  and  Knowledge   Organization  Systems  (KOS),  and  Prof.  Christopher  Baker:  A  renaissance  for  the   point  mutation:  from  legacy  data  to  semantic  web  service.  The  workshop  was   concluded  by  a  lively  panel  moderated  by  Ted  Slater  and  which  saw  Prof.  Jonas   Almeida,  Prof.  Chris  Baker,  Prof.  Ulf  Leser  and  Prof.  Chris  Bizer  as  panellists.   The  workshop  was  preceded  by  two  days  of  tutorials  whose  topics  have  been:     Semantic  Web  meets  Cloud  Computing,  Interoperable  Semantic  Web  Services,   D2RQ,  Query  Federation  with  SWObjects.  The  workshop  also  hosted  the  7th   Berlin  Semantic  Web  Meetup,  which  focused  on  Semantic  Health  Care  and  Life   Sciences.   These  proceedings  include  13  full  papers,  4  demo  papers  and  18  poster  papers.   The  presentations  and  tutorials  have  been  made  available  on  Nature  Precedings   (http://precedings.nature.com/collections/SWAT4LS-­‐2010).     We  wish  to  thank  the  sponsors  that  made  the  2010  edition  of  SWAT4LS  possible:     Ontotext,  Franz  Inc.,  Ontoprise  and  O'Reilly.     Furthermore,  we  would  like  to  thank  all  reviewers  of  the  papers  for  their   invaluable  contribution.