This cohort study prospectively evaluated the prevalence of the silicone-related symptom complex (SRSC) in relation to antinuclear antibodies (ANA) and magnetic resonance imaging (MRI) of silicone breast implants (SBI) 1 year after implantation. A total of 57 women undergoing mastectomy followed by immediate breast reconstruction (IBR) and SBI between March 1995 and March 1997 at the University Hospital Rotterdam/Daniel den Hoed Cancer Centre, were prospectively evaluated. Just before and 1 year after IBR the sera of these women were tested for the presence of ANA and they were screened for the prevalence of SRSC-related symptoms by questionnaire. All prostheses were evaluated by MRI 1 month and 1 year after IBR. Just before operation 11% of the women had a Sjögren score of more than 2, whereas 30% had such a score 1 year after IBR ( P = 0.01). One year postoperatively women had significantly more RA/Raynaud-related complaints: 21% preoperatively versus 40% 1 year after IBR ( P = 0.03). Within the undefined complaints-related group 19% had a score of 2 or more preoperatively and 33% 1 year after IBR ( P = 0.09). There were no new cases of ANA positivity 1 year after IBR. The linguine sign was seen by MRI in three implants: one 1 month after IBR and two 1 year after IBR. There was no relation to changes in SRSC expression and these MRI findings. In conclusion, 1 year after SBI implantation women had more SRSC-related complaints, especially Sjögren's and RA/Raynaud's. Moreover there was no correlation between elevated SRSC expression and changes in the presence of ANA or changes in MRI of the SBI 1 year after IBR.