Studies have supported and negated hypothesis, that hypocalcaemia is associated with hypertensive disorders of pregnancy (HDsP), mechanism is probably cellular. So serum and urinary levels do not reveal facts. Objective: Study was carried out to know relationship between serum calcium, urinary calcium, fetomaternal outcome, with early onset (EO), late onset (LO) HDsP. Materials and methods: Study subjects with singleton pregnancy beyond twenty weeks, diagnosed as gestational hypertension (GH), preeclampsia, eclampsia, over two years, were divided into EO (≥ 20 to <34 weeks gestation), LO (≥ 34 weeks), subdivided, category A (≥ 20 to <28 weeks), B (≥ 28 to <34 weeks), C (≥ 34 to <37 weeks), D (≥ 37 weeks), serum calcium, 24 h urinary calcium were measured. Pregnancy outcome was recorded. Results: In EO HDsP, 11.07% had mild GH, of them 53.3% and in LO 38.97% had mild GH, of them 27.48% had hypocalcaemia. Amongst severe PE, of category A 55%, B 58.33%, C 40%, D 41% had hypocalcaemia. Mean serum calcium in A was 8.13 mg/dl, B was 8.15 mg/dl, C was 8.25%, D was 8.28 mg/dl, low in EO, but insignificant difference. Mean 24 h calciuria in A was 114.5 mg/24 h, B, 110.6 mg/24 h, significantly more than LO, 101.34 mg/24 h in C, 89.45 mg/24 h in D. Mean 24 h calciuria was significantly low in LO. In A 36 (45.0%) of 80 patients had hypocalcaemia, 6 (16.8%) of them had spontaneous preterm births, in B, of 191 patients, 106 (55.50%) had hypocalcaemia, spontaneous preterm births in 16.9%. In LO of 475 of C, 190 (40.0%) had hypocalcaemia 6.8% had spontaneous preterm births, significantly less than EO, though had hypocalcaemia. Conclusion: Serum calcium was lower in EO than LO but difference insignificant. Many HDsP had hypocalciuria, mean 24 h calciuria was significantly more in EO compared to LO, difference in A, D significant. Studies are required to investigate further.