Aim The aim of the study is to investigate the trends in adult height between two consecutive surveys of NHFS and explore differences across variables such as gender, wealth, social groups etc. Methods We used the NFHS-II (1998-99), NFHS-III (2005-2006) and NFHS-IV (2015-16) (all three for women and last two for men) data to examine the trends in average height. Comparison was done between the two age strata of 15-25 and 26-50 years, across both male and female, to assess the trends. Results Between NFHS-III and NFHS-IV, the average height of women in the age group of 15-25 showed a decline by 0.12 cm 95% CI, -0.24 to 0.00, p-0.051 while in the 26-50 years age strata it demonstrated significant improvement in the mean height by 0.13 cm 95% CI, 0.02 to 0.023, p-0.015. However, Between NFHS III and IV, the average height of women in the poorest wealth index category registered a significant decline -0.57cm, 95% CI, -076 to -0.37, p-0.000. Between NFHS III and IV, the average height of Scheduled Tribe (ST) women in the age group of 15-25 years also exhibited a significant decline by 0.42 cm, 95% CI, -0.73 to -0.12, p-0.007. Among men, between the two surveys, both the age groups of 15-25 years and 26-50 years showed significant decline in average height: 1.10 cm 95% CI, -1.31 to -.099 cm, p-0.00 and 0.86 cm 95% CI, -1.03 to -0.69, p-0.000, respectively. Conclusion In the context of an overall increase in average heights worldwide the decline in average height of adults in India is alarming and demands an urgent enquiry. The argument for different standards of height for Indian population as different genetic group needs further scrutiny. However, the trends from India clearly underline the need to examine the non-genetic factors also to understand the interplay of genetic, nutritional and other social and environmental determinants on height.