Trevor Ndlovu was wounded several times on a Howick farm in June 2004 and died weeks later in Grey’s Hospital, Pietermaritzburg, and Mandla Masango was shot dead on a Balgowan farm in October 2004.
Hired killer Lucky Mlangeni, who pleaded guilty to both murders in 2009 and was sentenced to life imprisonment, testified for the State.
Judge Igna Stretch said there were no convincing reasons why Struwig should not be given the prescribed sentences for the pre-determined, finely planned murders.
For such murders retribution and punishment should take precedence over his rehabilitation.
She found that he was the middleman between farmers who wanted to be rid of their victims.
Lawmakers had enacted legislation laying down life sentences for such murders, unless there were good reasons for departing from them.
Throughout the trial of more than two years, Struwig denied guilt and appeared to show no remorse.
Struwig, 51, whose bail was revoked after he was convicted on Tuesday, stared straight ahead during sentencing.
Factors advanced in mitigation were that he had married his second wife two years ago, and adopted her three young children.
Further reasons given were Struwig worked as a building site manager with prospects for a possible a permanent position, visited family in Kempton Park during weekends, his wife worked, and was a successful businessman, employing many people.