This　paper　considers　the　control　problem　for　networked　control　systems　(NCSs)　with　unreliable　data　communication.　The　unreliable　data　communication　simultaneously　exists　in　both　control　channel　(from　controller　to　actuator)　and　measurement　channel　(from　sensor　to　controller)　and　may　cause　consecutive　packet　delays　and　losses.　A　new　model　is　established　based　on　all　possible　consecutive　packet　delays　and　losses.　The　observer-based　controller　is　designed　to　exponentially　stabilize　the　networked　system　in　the　sense　of　mean　square,　and　also　achieve　the　prescribed　H∞　disturbance　attenuation　level.　An　iterative　algorithm　is　developed　to　compute　the　optimal　H∞　disturbance　attenuation　and　the　controller　parameters　by　solving　the　semi-definite　programming　problem　via　interior-point　approach.　An　illustrative　example　is　provided　to　show　the　applicability　of　the　proposed　method.　©　2010　ICROS,　KIEE　and　Springer.