Background/Objective: Limited animal and human studies have shown function, albeit inadequate, of implanted thyroid tissue in muscles. This work aimed to ascertain results in a larger number of patients, finding practical method for implantation, studying the effect of changing weight of implant and effect of passage of time on its function. Methods: Forty patients had total thyroidectomy for simple multinodular goiters. A piece of the excised gland was finely minced, mixed with saline as emulsion, and injected in thigh muscles. Twelve patients had 5-g implants, while 28 patients had 10-g implants. Four parameters were studied at 2 months, 6 months, and 12 months: technetium isotope uptake by the implant; thyroid stimulating hormone (TSH); free T3 (FT3); and free T4 (FT4). Results: All autotransplanted thyroid tissue survived and functioned. After 12 months, mean values (± standard deviation) of isotope uptake, TSH, FT3, and FT4 of the 5-g implants were 0.44 ± 0.16%, 27.74 ± 30.4 UI/mL, 3.07 ± 1.10 pg/mL, and 1.01 ± 0.3 ng/dL, repectively. Those for the 10 g implants were 0.71 ± 0.20%, 22.78 ± 19.7 UI/mL, 3.92 ± 1.2 pg/mL, and 1.05 ± 0.3 ng/dL, repectively. Ten-gram implants showed significantly higher isotope uptake than 5-g. TSH, FT3, and FT4 significantly improved over the period of 1 year. Conclusion: Injection of thyroid tissue suspension is a simple method for thyroid autotransplantation. TSH was elevated in the majority to maintain normal or near normal thyroid hormones. Ten-gram implants showed higher isotope uptake than 5-g, although this difference was not reflected by thyroid hormone profile. The implant seemed to function better with the passage of time from 2 months to 12 months.