Crying is an unfortunate yet very likely side effect of sleep training, especially in babies and toddlers who are yet to formulate their opinions into words. Many parents feel they cannot commit to sleep training due to not being able to listen to their baby cry during the process. The cry of a baby has an innate function to not be ignored, so as parent (and as a sleep trainer!) it is very difficult to function and commit to sleep training whilst a baby is crying. However, if we can understand why a baby is crying and recognise the importance of continuing with sleep training, it makes it easier to deal with. When any kind of sleep training is undertaken, no matter how gentle the method, we are making changes to their routine so it is understandably confusing for a child who has been used to going to sleep in a particular way. We temporarily alter their ‘safe constant’ and until this new routine replaces their previous understanding of sleep and the sleep associations they have been used to, they are highly likely to let us know of their frustration! In babies and young children, this frustration is communicated in the only way they know how…crying. It is a completely normal part of sleep training, but the more consistent we are with implementing the new routine, the quicker and easier the transition is for all involved. Gentler methods of sleep training will greatly reduce the amount of crying, however, there may still be a certain level of crying involved.